spring属性注入（注入方式）

秒速五厘米 2022-04-23 06:22 357阅读 0赞

> ### 注入方式 ###

###  set方式注入： ###

User.java

public class User {
    	private String name;
    	private Integer age;
    	private Car car;
    	
    	public User() {
    		System.out.println("user构造");
    	}
    	
    	
    	public User(String name,Car car) {
    		super();
    		this.name = name;
    		this.car = car;
    	}
    	public User(Car car,String name) {
    		super();
    		this.name = name;
    		this.car = car;
    	}
    	
    
    	public Car getCar() {
    		return car;
    	}
    	
    	public void setCar(Car car) {
    		this.car = car;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public Integer getAge() {
    		return age;
    	}
    
    	public void setAge(Integer age) {
    		this.age = age;
    	}
    
    	@Override
    	public String toString() {
    		return "User [name=" + name + ", age=" + age + ", car=" + car + "]";
    	}
    
    	
    	
    	
    }

Car.java

public class Car {
    	private String name;
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	@Override
    	public String toString() {
    		return "Car [name=" + name + "]";
    	}
    	
    }

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd ">
    	
    	<bean name="user" class="cn.itcast.bean.User">
    		
    		<property name="name" value="jack"></property>
    		<property name="age" value="20"></property>
    		
    		<property name="car" ref="car"></property>
    	</bean>
    	
    	<bean name="car" class="cn.itcast.bean.Car">
    		<property name="name" value="大奔"></property>
    	</bean>
    	
    	
    	
    	
    </beans>

Demo:

@Test
    	public void fun1() {
    		ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
    		User user = (User) ac.getBean("user");
    		
    		System.out.println(user.toString());
    	}

效果：（控制台）

![20190124160746793.png][]

### 构造方式注入： ###

改applicationContext:

Demo（获取user2）

@Test
    	public void fun2() {
    		ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
    		User user = (User) ac.getBean("user2");
    		
    		System.out.println(user.toString());
    	}

效果：（控制台）

![20190124161149982.png][]

### 注意：上面User中有两个有参构造，只是顺序不一样，刚才用到是哪个？ ###

分别在两个构造上打印一句话

效果：（控制台）

![20190124161746959.png][]

那么怎么使用 public User(String name,Car car) ？

改applicationContext.xml (指定index属性)

<bean name="user2" class="cn.itcast.bean.User">
    		<constructor-arg name="name" value="tom" index="0"></constructor-arg>
    		<constructor-arg name="car" ref="car" index="1"></constructor-arg>
    	</bean>

效果：（控制台）

![20190124162014318.png][]

如果在User.java中添加构造

public User(Integer name,Car car) {
    		super();
    		this.name = name+"";
    		this.car = car;
    		System.out.println("33333Integer name,Car car");
    	}

改applicationContext.xml (指定type属性)

效果：（控制台）

![20190124162404826.png][]

[20190124160746793.png]: /images/20220323/031b026fa3574c20888bd0c34f087c90.png
[20190124161149982.png]: /images/20220323/3d741bf0a87c48d389ebbc93dea3d071.png
[20190124161746959.png]: /images/20220323/ec41e4298c0242a39200bb318d08c906.png
[20190124162014318.png]: /images/20220323/1ac5d2a426d745a584f4000aaac33e79.png
[20190124162404826.png]: /images/20220323/2282557d75584304bf9fdf6ce536f763.png