Spring——IOC创建对象的方式

private String name;

public User() {

    System.out.println("执行了User类的无参构造方法~");

}

public User(String name){

    this.name = name;

    System.out.println("执行了User类的有参构造方法");

}

//使用无参构造方法时，必须要设置set方法，因为注入时 需要通过set方法注入

public void setName(String name) {

    this.name = name;

}

@Override

public String toString() {

    return "User{" +

            "name='" + name + '\'' +

            '}';

}

   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

   xsi:schemaLocation="http://www.springframework.org/schema/beans

    https://www.springframework.org/schema/beans/spring-beans.xsd">

<bean id="user" class="com.test.pojo.User">

    <property name="name" value="gyp"/>

</bean>

public static void main(String[] args) {

    ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

    User user = context.getBean("user", User.class);

    System.out.println(user);

}

<bean id="user" class="com.test.pojo.User">

    <constructor-arg index="0" value="gyp"/>

</bean>

<bean id="user" class="com.test.pojo.User">

    <constructor-arg name="name" value="gyp"/>

</bean>

<bean id="user" class="com.test.pojo.User">

    <constructor-arg type="java.lang.String" value="gyp"/>

</bean>