1 概念和原理
1.1 什么是IOC?
-
IOC(控制反转),把对象的创建和对象之间调用的过程,交给Spring进行管理。
-
使用IOC的目的:为了降低耦合度。
1.2 IOC的底层原理
- xml解析、工厂设计模式、反射。
2 IOC接口(BeanFactory)
-
IOC思想基于IOC容器完成,IOC容器底层就是对象工厂。
-
Spring提供IOC容器实现的两种方式:
-
- BeanFactory:
-
-
- IOC容器最基本的实现方式,是Spring内部的使用接口,不提供开发人员进行使用。
-
-
-
- 加载配置文件的时候不会去创建对象,而是在获取对象(或使用对象)的时候才去创建对象。
-
-
- ApplicationContext:
-
-
- BeanFactory接口的子接口,提供更多更强大的功能,一般是由开发人员进行使用的。
-
-
-
- 加载配置的文件的时候就会立即创建对象。
-
-
-
- ApplicationContext接口的实现类。
-
3 IOC操作Bean管理
3.1 什么是Bean管理?
- Bean管理指的是Spring创建对象和Spring注入属性。
3.2 Bean管理的操作有两种实现方法
-
基于XML配置文件方式实现。
-
基于注解方式实现。
3.3 基于XML方式进行Bean管理的操作
3.3.1 基于XML方式创建对象
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--
在Spring配置文件中,使用bean标签,标签中添加对应的属性即可,就可以实现对象的创建。
在Bean标签中有很多属性,如下是一些常用的属性:
- id属性:唯一标识。
- class属性:类的全路径。
创建对象的时候,默认是调用的是无参构造方法。
-->
<bean id="user" class="top.open1024.spring.User"></bean>
</beans>
3.3.2 基于XML方式注入属性
- DI:依赖注入,就是注入属性。
3.3.2.1 创建对象和使用Setter方法进行注入
- Book.java
package top.open1024.spring;
public class Book {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="book" class="top.open1024.spring.Book">
<!--
使用property完成属性注入
name:类里面属性名称
value:向属性中注入的值
-->
<property name="name" value="红楼梦"/>
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Book book = context.getBean("book", Book.class);
System.out.println("book.getName() = " + book.getName());
}
}
3.3.2.2 有参构造注入属性
- Book.java
package top.open1024.spring;
public class Book {
private String name;
public Book(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="book" class="top.open1024.spring.Book" >
<constructor-arg name="name" value="西游记"/>
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Book book = context.getBean("book", Book.class);
System.out.println("book.getName() = " + book.getName());
}
}
3.3.2.3 p名称空间注入
p名称空间注入,可以简化Setter方法注入
- Book.java
package top.open1024.spring;
public class Book {
private String name;
private Double price;
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", price=" + price +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="book" class="top.open1024.spring.Book" p:name="红楼梦" p:price="20">
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Book book = context.getBean("book", Book.class);
System.out.println("book = " + book);
}
}
3.3.2.4 注入null和特殊字符
- Book.java
package top.open1024.spring;
public class Book {
private String name;
private Double price;
private String address;
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", price=" + price +
", address='" + address + '\'' +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="book" class="top.open1024.spring.Book">
<!--
null值
-->
<property name="name">
<null></null>
</property>
<!-- 属性值包含特殊字符 -->
<property name="address">
<value><![CDATA[<<江苏>>]]]></value>
</property>
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Book book = context.getBean("book", Book.class);
System.out.println("book = " + book);
}
}
3.3.2.5 注入属性-外部Bean
- UserDao.java
package top.open1024.spring.dao;
public interface UserDao {
public void update();
}
- UserDaoImpl.java
package top.open1024.spring.dao.impl;
import top.open1024.spring.dao.UserDao;
public class UserDaoImpl implements UserDao {
@Override
public void update() {
System.out.println("dao update....");
}
}
- UserService.java
package top.open1024.spring.service;
import top.open1024.spring.dao.UserDao;
public class UserService {
private UserDao userDao;
public UserDao getUserDao() {
return userDao;
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void update(){
System.out.println("service update...");
userDao.update();
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="userDao" class="top.open1024.spring.dao.impl.UserDaoImpl"></bean>
<bean id="userService" class="top.open1024.spring.service.UserService">
<property name="userDao" ref="userDao"></property>
</bean>
</beans>
- 测试
package top.open1024.spring;
import top.open1024.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class UserServiceTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = context.getBean("userService", UserService.class);
userService.update();
}
}
3.3.2.6 注入属性-内部Bean
- Dept.java
package top.open1024.spring;
import java.io.Serializable;
/**
* 部门
*/
public class Dept implements Serializable {
/**
* 部门名称
*/
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Dept{" +
"name='" + name + '\'' +
'}';
}
}
- Employee.java
package top.open1024.spring;
import java.io.Serializable;
/**
* 员工
*/
public class Employee implements Serializable {
/**
* 姓名
*/
private String name;
/**
* 性别
*/
private String gender;
/**
* 一个员工属于一个部门
*/
private Dept dept;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
@Override
public String toString() {
return "Employee{" +
"name='" + name + '\'' +
", gender='" + gender + '\'' +
", dept=" + dept +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="emp" class="top.open1024.spring.Employee">
<property name="name" value="张三"/>
<property name="gender" value="男"/>
<!--
设置内部Bean
-->
<property name="dept">
<bean id="dept" class="top.open1024.spring.Dept">
<property name="name" value="开发部"/>
</bean>
</property>
</bean>
</beans>
- 测试:
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class EmployeeTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Employee employee = context.getBean("emp", Employee.class);
System.out.println("employee = " + employee);
}
}
3.3.2.7 注入属性-级联赋值
- Dept.java
package top.open1024.spring;
import java.io.Serializable;
/**
* 部门
*/
public class Dept implements Serializable {
/**
* 部门名称
*/
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Dept{" +
"name='" + name + '\'' +
'}';
}
}
- Employee.java
package top.open1024.spring;
import java.io.Serializable;
/**
* 员工
*/
public class Employee implements Serializable {
/**
* 姓名
*/
private String name;
/**
* 性别
*/
private String gender;
/**
* 一个员工属于一个部门
*/
private Dept dept = new Dept();
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
@Override
public String toString() {
return "Employee{" +
"name='" + name + '\'' +
", gender='" + gender + '\'' +
", dept=" + dept +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="emp" class="top.open1024.spring.Employee">
<property name="name" value="张三"/>
<property name="gender" value="男"/>
<property name="dept.name" value="测试部"/>
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class EmployeeTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Employee employee = context.getBean("emp", Employee.class);
System.out.println("employee = " + employee);
}
}
3.3.2.8 注入集合类型属性
注入数组类型属性、注入List类型属性、注入Set类型属性、注入Map类型属性
- Student.java
package top.open1024.spring;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Student {
private String[] courses;
private List<String> list;
private Map<String, String> map;
private Set<String> set;
public String[] getCourses() {
return courses;
}
public void setCourses(String[] courses) {
this.courses = courses;
}
public List<String> getList() {
return list;
}
public void setList(List<String> list) {
this.list = list;
}
public Map<String, String> getMap() {
return map;
}
public void setMap(Map<String, String> map) {
this.map = map;
}
public Set<String> getSet() {
return set;
}
public void setSet(Set<String> set) {
this.set = set;
}
@Override
public String toString() {
return "Student{" +
"courses=" + Arrays.toString(courses) +
", list=" + list +
", map=" + map +
", set=" + set +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="student" class="top.open1024.spring.Student">
<property name="courses">
<array>
<value>Java课程</value>
<value>Linux课程</value>
<value>前端课程</value>
</array>
</property>
<property name="list">
<list>
<value>list1</value>
<value>list2</value>
<value>list3</value>
</list>
</property>
<property name="set">
<set>
<value>set1</value>
<value>set2</value>
<value>set3</value>
</set>
</property>
<property name="map">
<map>
<entry key="map-key1" value="map-value1"/>
<entry key="map-key2" value="map-value2"/>
<entry key="map-key2" value="map-value2"/>
</map>
</property>
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class StudentTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Student student = context.getBean("student", Student.class);
System.out.println("student = " + student);
}
}
3.3.2.9 注入集合对象类型
- Course.java
package top.open1024.spring;
public class Course {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Course{" +
"name='" + name + '\'' +
'}';
}
}
- Student.java
package top.open1024.spring;
import java.util.List;
public class Student {
private List<Course> courseList ;
public List<Course> getCourseList() {
return courseList;
}
public void setCourseList(List<Course> courseList) {
this.courseList = courseList;
}
@Override
public String toString() {
return "Student{" +
"courseList=" + courseList +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="student" class="top.open1024.spring.Student">
<property name="courseList">
<list>
<ref bean="java"></ref>
<ref bean="php"></ref>
</list>
</property>
</bean>
<bean id="java" class="top.open1024.spring.Course">
<property name="name" value="java"/>
</bean>
<bean id="php" class="top.open1024.spring.Course">
<property name="name" value="php"/>
</bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class StudentTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Student student = context.getBean("student", Student.class);
System.out.println("student = " + student);
}
}
3.3.2.10 工厂Bean
工厂Bean的步骤:
- ①创建类,让这个类作为工厂Bean,实现接口FactoryBean。
- ②实现接口里面的方法,在方法的定义中定义返回的Bean类型。
- Demo.java
package top.open1024.spring;
public class Demo {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Demo{" +
"name='" + name + '\'' +
'}';
}
}
- FactoryBeanDemo.java
package top.open1024.spring;
import org.springframework.beans.factory.FactoryBean;
public class FactoryBeanDemo implements FactoryBean<Demo> {
/**
* 定义返回Bean
*
* @return
* @throws Exception
*/
@Override
public Demo getObject() throws Exception {
Demo demo = new Demo();
demo.setName("这是一个Demo");
return demo;
}
@Override
public Class<?> getObjectType() {
return Demo.class;
}
@Override
public boolean isSingleton() {
return false;
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="demo" class="top.open1024.spring.FactoryBeanDemo"></bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DemoTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Demo demo = context.getBean("demo", Demo.class);
System.out.println("demo = " + demo);
}
}
3.3.3 Bean的作用域
3.3.3.1 概述
- 在Spring中,可以设置创建Bean实例是单实例还是多实例。
- 在Spring中,默认情况下,Bean是单实例对象。
3.3.3.2 单实例Bean
- Book.java
package top.open1024.spring;
public class Book {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="book" class="top.open1024.spring.Book"></bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Book book = context.getBean("book", Book.class);
Book book2 = context.getBean("book", Book.class);
System.out.println(book == book2);//true
}
}
3.3.3.3 多实例Bean
- Book.java
package top.open1024.spring;
public class Book {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--
默认情况下,scope的值是singleton,表示单实例Bean。
如果scope的值是prototype,则表示多实例Bean。
-->
<bean id="book" class="top.open1024.spring.Book" scope="prototype"></bean>
</beans>
- 测试
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Book book = context.getBean("book", Book.class);
Book book2 = context.getBean("book", Book.class);
System.out.println(book == book2);//false
}
}
3.3.3.4 总结
singleton和prototype的区别?
①singleton是单实例,prototype是多实例。
②设置scope的值是singleton的时候,加载Spring的配置文件的时候就会创建单实例对象。设置scope的值是prototype的时候,不是在加载Spring的配置文件的时候就会对象,而是在调用getBean()方法的时候创建对象。
3.3.4 Bean的生命周期
3.3.4.1 概述
- 生命周期:从对象的创建到对象的销毁的过程。
- Bean生命周期:
-
- ①通过构造器创建Bean实例(默认是通过无参构造器)
-
- ②为Bean的属性设置值和对其他Bean的引用(调用Setter方法)
- 调用Bean的初始化的方法(需要进行配置初始化的方法)。
-
- ④使用Bean对象。
-
- ⑤当容器的关闭的时候,会调用Bean的销毁方法(需要进行配置销毁的方法)。
3.3.4.2 应用示例
- Book.java
package top.open1024.spring;
public class Book {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
System.out.println("②调用setter方法设置属性值");
this.name = name;
}
public Book() {
System.out.println("①无参构造方法");
}
public void init() {
System.out.println("③这是初始化方法...");
}
public void destroy() {
System.out.println("⑤这是销毁的方法...");
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--
init-method配置初始化方法
destroy-method配置销毁方法
-->
<bean id="book" class="top.open1024.spring.Book" init-method="init" destroy-method="destroy">
<property name="name" value="哈哈"/>
</bean>
</beans>
- 测试:
package top.open1024.spring;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
//④调用Bean对象
Book book = context.getBean("book", Book.class);
System.out.println("④调用Bean对象" + book);
//手动调用让容器关闭
context.close();
}
}
3.3.4.3 后置处理器
-
后置处理器:会在Bean的初始化前后处理,将Bean传递给Bean的后置处理器方法
-
添加后置处理器的Bean的生命周期:
-
- ①通过构造器创建Bean实例(默认是通过无参构造器)
-
- ②为Bean的属性设置值和对其他Bean的引用(调用Setter方法)
-
- ③将Bean实例传递给Bean的后置处理器的方法。
-
- ④调用Bean的初始化的方法(需要进行配置初始化的方法)。
-
- ⑤将Bean实例传递给Bean的后置处理器的方法。
-
- ⑥使用Bean对象。
-
- ⑦当容器的关闭的时候,会调用Bean的销毁方法(需要进行配置销毁的方法)。
-
示例:只需要让类实现BeanPostProcessor,并重写其中的方法即可。
-
Book.java
package top.open1024.spring;
public class Book {
public void init(){
System.out.println("Book初始化...");
}
}
- Demo.java
package top.open1024.spring;
public class Demo {
public void init(){
System.out.println("Demo初始化...");
}
}
- MyBeanPostProcessor.java
package top.open1024.spring;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
public class MyBeanPostProcessor implements BeanPostProcessor {
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
System.out.println("初始化前...");
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
System.out.println("初始化后...");
return bean;
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="book" class="top.open1024.spring.Book" init-method="init" ></bean>
<bean id="demo" class="top.open1024.spring.Demo" init-method="init"></bean>
<!--配置后置处理器-->
<bean id="myBeanPostProcessor" class="top.open1024.spring.MyBeanPostProcessor"></bean>
</beans>
- 测试:
package top.open1024.spring;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class BookTest {
public static void main(String[] args) {
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
}
}
3.3.5 自动装配
3.5.5.1 概述
- 根据指定装配规则(属性名称或属性类型),Spring自动将匹配的属性值进行注入。
3.5.5.2 应用示例
- 示例:根据属性名称自动注入
package top.open1024.spring;
import java.io.Serializable;
public class Dept implements Serializable {
@Override
public String toString() {
return "Dept{}";
}
}
- Employee.java
package top.open1024.spring;
import java.io.Serializable;
public class Employee implements Serializable {
private Dept dept;
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
@Override
public String toString() {
return "Employee{" +
"dept=" + dept +
'}';
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="dept" class="top.open1024.spring.Dept"></bean>
<!--
实现自动装配
bean标签中有属性autowire:
- 属性值 byName,根据属性名注入,注入Bean的id值要和类属性一致
- 属性值 byType,根据属性类型注入,注入Bean的类型要和类属性类型一致
-->
<bean id="emp" class="top.open1024.spring.Employee" autowire="byName"></bean>
</beans>
- 测试:
package top.open1024.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class EmployeeTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
Employee employee = context.getBean("emp",Employee.class);
System.out.println("employee = " + employee);
}
}
3.3.6 外部属性文件
- 示例:通过引入外部属性文件配置数据库连接池
- 导入数据库连接池的Maven坐标
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.23</version>
</dependency>
- db.properties
jdbc.url=jdgc:mysql://localhost:3306/db01
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.user=root
jdbc,password=123456
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<!-- 引入外部属性文件 -->
<context:property-placeholder location="db.properties"></context:property-placeholder>
<!-- 配置数据库连接池 -->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${jdbc.driverClass}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.user}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
</beans>
3.4 基于注解方式进行Bean管理的操作
3.4.1 什么是注解?
- 注解是代码的一种特殊标记,注解可以作用在类、方法和属性上面。
- 语法:
@注解名称(属性名称=属性值,属性名称=属性值...)
- 使用注解的目的,是简化XML的配置。
3.4.2 Spring针对Bean管理中创建对象提供的注解
- @Component
- @Service
- @Controller
- @Repository
上面的四个注解功能是一样的,都可以用来创建Bean实例。
3.4.3 基于注解方式创建对象
• 示例:
• UserService.java
package top.open1024.spring.service;
import org.springframework.stereotype.Service;
/**
* 在注解里面value属性值可以省略不写,默认值是类名首字母小写
*/
@Service(value = "userService")
public class UserService {
public void add() {
System.out.println("UserService ...");
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<!--
开启组件扫描
如果扫描多个包,多个包之间使用,隔开
如果扫描多个包,可以使用扫描包的是上层目录
-->
<context:component-scan base-package="top.open1024.spring"></context:component-scan>
</beans>
- 测试:
package top.open1024.spring;
import top.open1024.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class EmployeeTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = context.getBean("userService", UserService.class);
userService.add();
}
}
3.4.4 基于注解注入属性
3.4.4.1 概述
-
Spring注入属性提供的注解:
-
- @Autowired:根据属性类型进行自动装配。
-
- @Qualifier:根据属性名称进入注入。
-
- @Resource:可以根据类型注入,也可以根据名称注入。
-
- @Value:注入普通类型属性
3.4.4.2 @Autowired注解的使用
- 示例:
- UserDao.java
package top.open1024.spring.dao;
public interface UserDao {
void add();
}
- UserDaoImpl.java
package top.open1024.spring.dao.impl;
import top.open1024.spring.dao.UserDao;
import org.springframework.stereotype.Repository;
@Repository
public class UserDaoImpl implements UserDao {
@Override
public void add() {
System.out.println("UserDaoImpl。。。add。。。");
}
}
- UserService.java
package top.open1024.spring.service;
public interface UserService {
void add();
}
- UserServiceImpl.java
package top.open1024.spring.service.impl;
import top.open1024.spring.dao.UserDao;
import top.open1024.spring.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl implements UserService {
//@Autowired按照类型注入
@Autowired
private UserDao userDao;
@Override
public void add() {
System.out.println("UserServiceImpl...add...");
userDao.add();
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-package="top.open1024.spring"></context:component-scan>
</beans>
- 测试:
package top.open1024.spring;
import top.open1024.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Spring5Test {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = context.getBean("userServiceImpl", UserService.class);
userService.add();
}
}
3.4.4.3 @Qualifier注解的使用
- UserDao.java
package top.open1024.spring.dao;
public interface UserDao {
void add();
}
- UserDaoImpl.java
package top.open1024.spring.dao.impl;
import top.open1024.spring.dao.UserDao;
import org.springframework.stereotype.Repository;
@Repository
public class UserDaoImpl implements UserDao {
@Override
public void add() {
System.out.println("UserDaoImpl。。。add。。。");
}
}
- UserService.java
package top.open1024.spring.service;
public interface UserService {
void add();
}
- UserServiceImpl.java
package top.open1024.spring.service.impl;
import top.open1024.spring.dao.UserDao;
import top.open1024.spring.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl implements UserService {
//@Qualifier注解按照属性名称注入,其中属性value的值是要注入Bean的id
//@Qualifier注解要和@Autowired配合使用
@Autowired
@Qualifier(value = "userDaoImpl")
private UserDao userDao;
@Override
public void add() {
System.out.println("UserServiceImpl...add...");
userDao.add();
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-package="top.open1024.spring"></context:component-scan>
</beans>
- 测试:
package top.open1024.spring;
import top.open1024.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Spring5Test {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = context.getBean("userServiceImpl", UserService.class);
userService.add();
}
}
3.4.4.4 @Resource注解的使用
- UserDao.java
package top.open1024.spring.dao;
public interface UserDao {
void add();
}
- UserDaoImpl.java
package top.open1024.spring.dao.impl;
import top.open1024.spring.dao.UserDao;
import org.springframework.stereotype.Repository;
@Repository
public class UserDaoImpl implements UserDao {
@Override
public void add() {
System.out.println("UserDaoImpl。。。add。。。");
}
}
- UserService.java
package top.open1024.spring.service;
public interface UserService {
void add();
}
- UserServiceImpl.java
package top.open1024.spring.service.impl;
import top.open1024.spring.dao.UserDao;
import top.open1024.spring.service.UserService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class UserServiceImpl implements UserService {
//@Resource注解如果不写name属性,那么就是按照类型注入
//@Resource注解如果写name属性,那么就是按照名称注入
@Resource(name = "userDaoImpl")
private UserDao userDao;
@Override
public void add() {
System.out.println("UserServiceImpl...add...");
userDao.add();
}
}
- applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-package="top.open1024.spring"></context:component-scan>
</beans>
- 测试:
package top.open1024.spring;
import top.open1024.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Spring5Test {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = context.getBean("userServiceImpl", UserService.class);
userService.add();
}
}
3.4.5 完全注解开发
3.4.5.1 开发步骤
-
①创建一个配置类,用来替代applicationContext.xml文件。
-
②测试的时候,使用的是AnnotationConfigApplicationContext,而不是ClassPathXmlApplicationContext。
3.4.5.2 应用示例
- UserDao.java
package top.open1024.spring.dao;
public interface UserDao {
void add();
}
- UserDaoImpl.java
package top.open1024.spring.dao.impl;
import top.open1024.spring.dao.UserDao;
import org.springframework.stereotype.Repository;
@Repository
public class UserDaoImpl implements UserDao {
@Override
public void add() {
System.out.println("UserDaoImpl。。。add。。。");
}
}
- UserService.java
package top.open1024.spring.service;
public interface UserService {
void add();
}
- UserServiceImpl.java
package top.open1024.spring.service.impl;
import top.open1024.spring.dao.UserDao;
import top.open1024.spring.service.UserService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class UserServiceImpl implements UserService {
//@Resource注解如果不写name属性,那么就是按照类型注入
//@Resource注解如果写name属性,那么就是按照名称注入
@Resource(name = "userDaoImpl")
private UserDao userDao;
@Override
public void add() {
System.out.println("UserServiceImpl...add...");
userDao.add();
}
}
- SpringConfing.java
package top.open1024.spring.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
/**
* 配置类,相当于applicationContext.xml
*/
@Configuration
@ComponentScan(basePackages = "top.open1024.spring")
public class SpringConfig {
}
- 测试:
package top.open1024.spring;
import top.open1024.spring.config.SpringConfig;
import top.open1024.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class Spring5Test {
public static void main(String[] args) {
ApplicationContext context = new AnnotationConfigApplicationContext(SpringConfig.class);
UserService userService = context.getBean("userServiceImpl", UserService.class);
userService.add();
}
}
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