6_Spring_Bean的自动装配

6_Spring_Bean的自动装配

bean自动装配

通过property标签可以手动指定给属性进行注入

我们也可以通过自动转配,完成属性的自动注入,就是自动装配,可以简化DI的配置

准备实体类

1. package com.msb.bean;

2. /**

3. • @Author: Ma HaiYang
4. • @Description: MircoMessage:Mark_7001

5. */

6. public class Dept {

7. }

8. package com.msb.bean;

9. /**

10. • @Author: Ma HaiYang
11. • @Description: MircoMessage:Mark_7001

12. */

13. public class Emp {

14.  private Dept dept;
    

15.  @Override
    

16.  public String toString() {
    

17.     return "Emp{" +
    

18.             "dept=" + dept +
    

19.             '}';
    

20. }
    

21. public Dept getDept() {
    

22.     return dept;
    

23. }
    

24. public void setDept(Dept dept) {
    

25.     this.dept = dept;
    

26. }
    

27. public Emp() {
    

28. }
    

29. public Emp(Dept dept) {
    

30.     this.dept = dept;
    

31. }
    

32. }

配置文件

2. <beans xmlns="http://www.springframework.org/schema/beans"

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

4.     xmlns:p="http://www.springframework.org/schema/p"
   

5.     xmlns:c="http://www.springframework.org/schema/c"
   

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

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

8.  <bean id="dept" class="com.msb.bean.Dept"></bean>
   

9.  <!--
   

10. autowire 属性控制自动将容器中的对象注入到当前对象的属性上
    

11. byName 根据目标id值和属性值注入,要保证当前对象的属性值和目标对象的id值一致
    

12. byType 根据类型注入,要保证相同类型的目标对象在容器中只有一个实例
    

13. -->
    

14. <bean id="emp" class="com.msb.bean.Emp" autowire="byName"></bean>
    

测试代码

1. package com.msb.test;
2. import com.msb.bean.Emp;
3. import com.msb.bean.User;
4. import org.junit.Test;
5. import org.springframework.context.support.ClassPathXmlApplicationContext;
6. /**
7. • @Author: Ma HaiYang
8. • @Description: MircoMessage:Mark_7001
9. */
10. public class Test2 {

11. @Test
    

12. public void testGetBean(){
    

13.     ClassPathXmlApplicationContext context =new
    

    ClassPathXmlApplicationContext("applicationContext2.xml");

14.     Emp emp = context.getBean("emp", Emp.class);
    

15.     System.out.println(emp);
    

16. }
    

17. }

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