spring框架学习四（ioc如何创建对象）

IOC

1.无参构造创建对象，

2.实体类
package com.yms.entity;

/**

• @Author 杨明书
• @PackageName: com.yms.entity
• @ClassName: User
• @Description:
• @Date: 2021/12/29 14:11
  */
  public class User {
  private String name;

// public User(){
// System.out.println("user 的无参构造");
// }

public User(String name){
    this.name=name;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public void  show(){
    System.out.println("姓名为："+name);
}

}

3.配置文件

<bean id="user" class="com.yms.entity.User">
   <!--        无参赋值-->

    <constructor-arg name="name" value="钟无艳"></constructor-arg>
</bean>

4.测试类
import com.yms.entity.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**

• @Author 杨明书
• @PackageName: PACKAGE_NAME
• @ClassName: MyTest
• @Description:
• @Date: 2021/12/29 14:13
  */
  public class MyTest {
  public static void main(String[] args) {
  ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
  User user = (User) context.getBean("user");
  user.show();

// User user = new User();

}

}