spring框架学习三（IOC）

实体类

package com.yms.hello;

/**

• @Author 杨明书

• @PackageName: com.yms.hello

• @ClassName: Hello

• @Description:

• @Date: 2021/12/29 11:28
  */
  public class Hello {
  private String str;

  public String getStr() {
  return str;
  }

  public void setStr(String str) {
  this.str = str;
  }

  @Override
  public String toString() {
  return "Hello{" +
  "str='" + str + ''' +
  '}';
  }
  }

配置文件

<bean id="hello" class="com.yms.hello.Hello">
    <property name="str" value="hello world"></property>
</bean>

测试类

import com.yms.hello.Hello;
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 11:40
  */
  public class MyTest {
  public static void main(String[] args) {
  //获取spring的上下文对象
  ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
  //现在我们的对象放在spring中管理
  Hello hello = (Hello) context.getBean("hello");
  System.out.println(hello.toString());

  }
  }

总结：ioc是一种编程思想，一句话，对象由spring创建，管理，装配。

配置文件

<bean id="user" class="com.yms.dao.impl.UserDaoImpl"/>
<bean id="mysql" class="com.yms.dao.impl.UserDaoMysql"/>
<bean id="oracle" class="com.yms.dao.impl.UserDaoOracle"/>

<bean id="t" class="com.yms.service.impl.UserServiceImpl">
    <property name="userDao" ref="mysql"></property>
 </bean>

测试类

import com.yms.dao.impl.UserDaoImpl;
import com.yms.dao.impl.UserDaoMysql;
import com.yms.dao.impl.UserDaoOracle;
import com.yms.service.UserService;
import com.yms.service.impl.UserServiceImpl;
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 10:16
  */
  public class MyTest {
  public static void main(String[] args) {
  // UserService userService = new UserServiceImpl();
  // userService.getUser();
  // UserDaoMysql mysql = new UserDaoMysql();
  // mysql.getUser();
  // UserDaoOracle userDaoOracle = new UserDaoOracle();
  // userDaoOracle.getUser();
  //
  // UserServiceImpl userService = new UserServiceImpl();
  // userService.setUserDao(new UserDaoMysql());
  // userService.getUser();

// UserServiceImpl userService = new UserServiceImpl();
// userService.getUser();
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
UserServiceImpl userService = (UserServiceImpl) context.getBean("t");
userService.getUser();

}

}