Spring 两种bean依赖注入方式

类：

1，构造器方式

类CCC：必须有构造器

package com.xxx;

public class CCC {
    private int D1;
    private String D2;
    private String D3;

    public CCC(int d1, String d2, String d3) {
        D1 = d1;
        D2 = d2;
        D3 = d3;
    }
}

2，set方式

不能有构造器

package com.xxx;

public class CCC {
    private int D1;
    private String D2;
    private String D3;

    public void setD1(int d1) {
        D1 = d1;
    }
    public void setD2(String d2) {
        D2 = d2;
    }
    public void setD3(String d3) {
        D3 = d3;
    }
}

applicationContext.xml文件

1，构造器方式

使用<constructor-arg name="D1" value="1"></constructor-arg>的方式设置类属性值

<?xml version="1.0" encoding="UTF8" ?>
<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="user1" class="com.xxx.CCC">
        <constructor-arg name="D1" value="1"></constructor-arg>
        <constructor-arg name="D3" value="d2"></constructor-arg>
        <constructor-arg name="D3" value="d3"></constructor-arg>
    </bean>
</beans>

2，set方式

<?xml version="1.0" encoding="UTF8" ?>
<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="user1" class="com.xxx.CCC">
        <property name="D1" value="1"></property>
        <property name="D3" value="d2"></property>
        <property name="D3" value="d3"></propertyg>
    </bean>
</beans>