SSH与SSM学习之Spring07——Spring属性注入之spel注入

SSH与SSM学习之Spring07——Spring属性注入之spel注入

一、spel注入

#{变量}

<bean name="user7" class="com.qwm.spring1.bean.User">
<property name="name" value="#{user2.name}"/>
<property name="age" value="#{user2.age}"/>
<property name="car" ref="car"/>
</bean>

二、Car类

package com.qwm.spring1.bean;
/**
* @author: wiming
* @date: 2017-09-27 14:59:50  星期三
* @decription:
*/
public class Car {
private String color;
private String name;

public String getColor() { return color; }
public void setColor(String color) { this.color = color; }
public String getName() { return name; }
public void setName(String name) { this.name = name; }

@Override public String toString() { return "Car{color='" + color + '\'' + ", name='" + name + '\'' + '}'; }
}

三、User类

package com.qwm.spring1.bean;

import java.io.Serializable;

/**
* @author: wiming
* @date: 2017-09-25 14:45:56  星期一
* @decription:
*/
public class User implements Serializable {
private String name;
private int age;
private Car car;

public User() {
System.out.println("User实例化了----" + this);
}

public User(String name, int age) {
this.name = name;
this.age = age;
System.out.println("构造方法: User(String name, int age)");
}

public User(int name, int age) {
this.name = name + "";
this.age = age;
System.out.println("构造方法: User(int name, int age)");
}

public User(int age, String name) {
this.name = name;
this.age = age;
System.out.println("构造方法: User(int age, String name)");
}

public User(String name, int age, Car car) {
this.name = name;
this.age = age;
this.car = car;
System.out.println("构造方法: User(String name, int age, Car car)");
}

public void init() { System.out.println("---User---init---"); }
public void destory() { System.out.println("---User---destory---"); }

public String getName() { return name; }
public void setName(String name) { this.name = name; }
public int getAge() { return age; }
public void setAge(int age) { this.age = age; }
public Car getCar() { return car; }
public void setCar(Car car) { this.car = car; }

@Override
public String toString() {
return "User{name='" + name + '\'' + ", age=" + age + ", car=" + car + '}';
}
}

四、配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd ">

<!--Car配置-->
<bean name="car" class="com.qwm.spring1.bean.Car">
<!--值类型注入-->
<property name="name" value="兰博基尼"/>
<property name="color" value="红色"/>
</bean>

<!--=============构造方法注入测试============-->
<!--constructor-arg 使用构造函数的时候，是用来给参数赋值-->
<!-- name属性: 构造函数的参数名 -->
<!-- index属性: 构造函数的参数索引 -->
<!-- type属性: 构造函数的参数类型-->
<!--User(int age, String name)-->
<bean name="user2" class="com.qwm.spring1.bean.User">
<constructor-arg name="name" value="qiwenming"/>
<constructor-arg name="age" value="18"/>
<property name="car" ref="car"/>
</bean>

<!--=============spel注入============-->
<!-- spel注入: spring Expression Language sping表达式语言-->
<bean name="user7" class="com.qwm.spring1.bean.User">
<property name="name" value="#{user2.name}"/>
<property name="age" value="#{user2.age}"/>
<property name="car" ref="car"/>
</bean>
</beans>

五、测试代码

@Test
public void test7(){
ApplicationContext ac = new ClassPathXmlApplicationContext("com/qwm/spring1/c_inject/applicationContext.xml");
User user = (User) ac.getBean("user7");
System.out.println(user);
}

六、运行结果

构造方法: User(int age, String name)
User实例化了----User{name='null', age=0, car=null}
User{name='qiwenming', age=18, car=Car{color='红色', name='兰博基尼'}}

七、源码下载