1、創(chuàng)建對象時，向類屬性里面設置值

2、java屬性注入的三種方式

• set方法

  
  
  image.png

• 有參構造

  
  
  image.png

• 接口注入

  
  
  image.png

3、在spring中只支持兩種方式

（1）set方法注入

PropertyUser.java

package work.zhangdoudou.Property;

public class PropertyUser {
    private String username;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }   
}

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-3.0.xsd">
    <!-- set方法注入屬性 -->
    <bean id="propertyUser" class="work.zhangdoudou.Property.PropertyUser">
        <!-- set方法注入屬性 -->
        <property name="username" value="lisi"></property>
    </bean>
</beans>

測試類TestPropertyUser.java

package work.zhangdoudou.test;

import static org.junit.Assert.*;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import work.zhangdoudou.Property.PropertyUser;

public class TestPropertyUser {

    @Test
    public void test() {
        //1加載配置文件，根據(jù)創(chuàng)建對象
        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
        //2得到創(chuàng)建的對象
        PropertyUser propertyUser=(PropertyUser) context.getBean("propertyUser");
        System.out.println(propertyUser.getUsername());
    }

}

運行結果

image.png

（2）有參數(shù)構造注入

PropertyUser1.java

package work.zhangdoudou.Property;

public class PropertyUser1 {
    private String username;

    public PropertyUser1(String username) {
        this.username = username;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }   
}

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-3.0.xsd"> 
    <!-- 有參數(shù)構造注入屬性 -->
    <bean id="propertyUser1" class="work.zhangdoudou.Property.PropertyUser1">
        <!-- 有參數(shù)構造注入 -->
        <constructor-arg name="username" value="zhangsan"></constructor-arg>
    </bean>
</beans>

測試類TestPropertyUser1.java

package work.zhangdoudou.test;

import static org.junit.Assert.*;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import work.zhangdoudou.Property.PropertyUser1;

public class TestPropertyUser1 {

    @Test
    public void test() {
        //1加載配置文件，根據(jù)創(chuàng)建對象
        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
        //2得到創(chuàng)建的對象
        PropertyUser1 propertyUser1=(PropertyUser1) context.getBean("propertyUser1");
        System.out.println(propertyUser1.getUsername());
    }

}

運行結果

image.png