Spring依赖注入DI

bean的注入方式主要有以下三种：
- 属性注入 (默认方式，最为常用)
- 构造注入
- 工厂方法注入 (不用)

一、属性注入：（javabean中得有无参构造方法）

<!-- 配置bean -->
<bean id="student" class="com.edu.bean.Student">
    <property name="name" value="小明"></property>
    <property name="gender" value="男"></property>
</bean>

二、构造注入：（javabean里得有有参构造方法）

<!-- 配置bean -->
<bean class="com.edu.bean.Student">
    <constructor-arg name="name" value="小明"></constructor-arg>
    <constructor-arg name="gender" value="男"></constructor-arg>
</bean>

如果javabean中属性是int，容器也会自动转换

public class Student {
  private Integer id;
  private String name;
  private String gender;
}    

<!-- 配置bean -->
<bean id="studentConstructor" class="com.edu.bean.Student">
  <constructor-arg name="id" value="1"/>
  <constructor-arg name="name" value="小明"/>
  <constructor-arg name="gender" value="男"/>
</bean>

三、属性注入之常见方式

1、学生类中有另一类属性（学生类有个classroom属性）

javabean

  public class ClassRoom {
      private int cid;
      private String name;
  }

  public class Student {
    private Integer id;
    private String name;
    private String gender;
    private Classroom classroom;
  }

xml配置

1>外部连接

<bean id="classroom" class="com.edu.bean.Classroom">
    <property name="cid" value="1"/>
    <property name="name" value="一班"/>
</bean>
<bean id="studentClassroom1" class="com.edu.bean.Student">
    <property name="id" value="2"/>
    <property name="name" value="小华"/>
    <property name="gender" value="男"/>
    <property name="classroom" ref="classroom"/>
</bean>

2>内部bean

<bean id="studentClassroom2" class="com.edu.bean.Student">
    <property name="id" value="3"/>
    <property name="name" value="小花"/>
    <property name="gender" value="女"/>
    <property name="classroom">
        <bean class="com.edu.bean.Classroom">
            <property name="cid" value="3"/>
            <property name="name" value="三班"/>
        </bean>
    </property>
</bean>

测试

@Test
public void testStudentClassroom() {
   ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
   Student student = (Student)applicationContext.getBean("studentClassroom1");//studentClassroom2
   System.out.println(student);
}

2、Classrom类中有list

javabean

  public class ClassRoom {
      private int cid;
      private String name;
      private List<Student> studentList;
  }

  public class Student {
    private Integer id;
    private String name;
    private String gender;
  }

xml配置

<bean id="classroomList" class="com.edu.bean.Classroom">
    <property name="cid" value="2"/>
    <property name="name" value="二班"/>
    <property name="studentList">
        <list>
            <ref bean="studentClassroom1"/>
            <bean class="com.edu.bean.Student">
                <property name="id" value="2"/>
                <property name="name" value="小雷"/>
                <property name="gender" value="男"/>
                <property name="classroom">
                    <ref bean="classroom"/>
                </property>
            </bean>
        </list>
    </property>
 </bean>

此案例list中一个classroom来自外部，一个是内部bean 配置数组也是用list标签，而set集合使用set标签，基本使用一样。

测试

  @Test
  public void testClassroomList() {
     ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
     Student student = (Student)applicationContext.getBean("classroomList");
     System.out.println(student);
  }

3、Classrom类中有array

javabean

  public class ClassRoom {
      private int cid;
      private String name;
      private Student studentArray[];
  }

  public class Student {
    private Integer id;
    private String name;
    private String gender;
  }

xml配置

<bean id="classroomArray" class="com.edu.bean.Classroom">
    <property name="cid" value="6"/>
    <property name="name" value="六班"/>
    <property name="studentArray">
        <list>
            <bean class="com.edu.bean.Student">
                <property name="id" value="8"/>
                <property name="name" value="花花"/>
            </bean>
            <bean class="com.edu.bean.Student">
                <property name="id" value="9"/>
                <property name="name" value="蕾蕾"/>
            </bean>
        </list>
    </property>
</bean>

测试

  @Test
  public void testClassroomArray() {
     ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
     Student student = (Student)applicationContext.getBean("classroomArray");
     System.out.println(student);
  }

4、Classrom类中有set

javabean

  public class ClassRoom {
      private int cid;
      private String name;
      private Set<Student> studentSet;
  }

  public class Student {
    private Integer id;
    private String name;
    private String gender;
  }

xml配置

1>set标签

<bean id="classroomSet1" class="com.edu.bean.Classroom">
     <property name="cid" value="9"/>
     <property name="name" value="九班"/>
     <property name="studentSet">
         <set>
             <bean class="com.edu.bean.Student">
                 <property name="id" value="8"/>
                 <property name="name" value="花花"/>
             </bean>
             <bean class="com.edu.bean.Student">
                 <property name="id" value="9"/>
                 <property name="name" value="蕾蕾"/>
             </bean>
         </set>
     </property>
 </bean>

2>lait标签

 <bean id="classroomSet2" class="com.edu.bean.Classroom">
     <property name="cid" value="10"/>
     <property name="name" value="十班"/>
     <property name="studentSet">
         <list>
             <bean class="com.edu.bean.Student">
                 <property name="id" value="8"/>
                 <property name="name" value="花花"/>
             </bean>
             <bean class="com.edu.bean.Student">
                 <property name="id" value="9"/>
                 <property name="name" value="蕾蕾"/>
             </bean>
         </list>
     </property>
 </bean>

测试

  @Test
  public void testClassroomSet() {
     ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
     Student student = (Student)applicationContext.getBean("classroomSet1");//classroomSet2
     System.out.println(student);
  }

5、Classrom类中有map

javabean

  public class ClassRoom {
      private int cid;
      private String name;
      private Map<String,Student> studentMap;
  }

  public class Student {
    private Integer id;
    private String name;
    private String gender;
  }

xml配置

<bean id="classroomMap" class="com.edu.bean.Classroom">
    <property name="cid" value="90"/>
    <property name="name" value="九十班"/>
    <property name="studentMap">
        <map>
            <entry key="aa" value-ref="student"/>
            <entry key="bb">
                <bean class="com.edu.bean.Student">
                    <property name="id" value="100"/>
                    <property name="name" value="大炮"/>
                </bean>
            </entry>
        </map>
    </property>
</bean>

测试

  @Test
  public void testClassroomMap() {
     ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
     Student student = (Student)applicationContext.getBean("classroomMap");
     System.out.println(student);
  }

四、使用p命名空间为属性赋值:

javabean

      public class Student {
        private Integer id;
        private String name;
        private String gender;
      }

xml配置

<bean id="studentP" class="com.edu.bean.Student" p:id="99" p:name="狗蛋" p:gender="男"></bean>

测试

@Test
public void testClassroomMap() {
   ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
   Student student = (Student)applicationContext.getBean("studentP");
   System.out.println(student);
}

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Spring依赖注入DI.md

Spring依赖注入DI.md

Spring依赖注入DI

一、属性注入：（javabean中得有无参构造方法）

二、构造注入：（javabean里得有有参构造方法）

三、属性注入之常见方式

四、使用p命名空间为属性赋值:

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Spring依赖注入DI.md

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Spring依赖注入DI

一、属性注入：（javabean中得有无参构造方法）

二、构造注入：（javabean里得有有参构造方法）

三、属性注入之常见方式

四、使用p命名空间为属性赋值: