Spring的DI依赖注入详解

package com.ys.di;
 
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
 
public class Person {
    private Long pid;
    private String pname;
    private Student students;
    private List lists;
    private Set sets;
    private Map maps;
    private Properties properties;
     
    public Long getPid() {
        return pid;
    }
    public void setPid(Long pid) {
        this.pid = pid;
    }
    public String getPname() {
        return pname;
    }
    public void setPname(String pname) {
        this.pname = pname;
    }
    public Student getStudents() {
        return students;
    }
    public void setStudents(Student students) {
        this.students = students;
    }
    public List getLists() {
        return lists;
    }
    public void setLists(List lists) {
        this.lists = lists;
    }
    public Set getSets() {
        return sets;
    }
    public void setSets(Set sets) {
        this.sets = sets;
    }
    public Map getMaps() {
        return maps;
    }
    public void setMaps(Map maps) {
        this.maps = maps;
    }
    public Properties getProperties() {
        return properties;
    }
    public void setProperties(Properties properties) {
        this.properties = properties;
    }
     
}

<!--
    property是用来描述一个类的属性
    基本类型的封装类、String等需要值的类型用value赋值
    引用类型用ref赋值
-->
<bean id="person" class="com.ys.di.Person">
    <property name="pid" value="1"></property>
    <property name="pname" value="vae"></property>
    <property name="students">
        <ref bean="student"/>
    </property>
     
    <property name="lists">
        <list>
            <value>1</value>
            <ref bean="student"/>
            <value>vae</value>
        </list>
    </property>
     
    <property name="sets">
        <set>
            <value>1</value>
            <ref bean="student"/>
            <value>vae</value>
        </set>
    </property>
     
    <property name="maps">
        <map>
            <entry key="m1" value="1"></entry>
            <entry key="m2" >
                <ref bean="student"/>
            </entry>
        </map>
    </property>   
     
    <property name="properties">
        <props>
            <prop key="p1">p1</prop>
            <prop key="p2">p2</prop>
        </props>
    </property>  
     
</bean>
 
 
<bean id="student" class="com.ys.di.Student"></bean>

//利用 set 方法给对象赋值
    @Test
    public void testSet(){
        //1、启动 spring 容器
        //2、从 spring 容器中取出数据
        //3、通过对象调用方法
        ApplicationContext context =
                new ClassPathXmlApplicationContext("applicationContext.xml");
        Person person = (Person) context.getBean("person");
        System.out.println(person.getPname());//vae
    }

//默认构造函数
    public Person(){}
    //带参构造函数
    public Person(Long pid,Student students){
        this.pid = pid;
        this.students = students;
    }

<!-- 根据构造函数赋值 -->
    <!--
        index  代表参数的位置  从0开始计算
        type   指的是参数的类型,在有多个构造函数时，可以用type来区分，要是能确定是那个构造函数，可以不用写type
        value  给基本类型赋值
        ref    给引用类型赋值
      -->
    <bean id="person_con" class="com.ys.di.Person">
        <constructor-arg index="0" type="java.lang.Long" value="1">
        </constructor-arg>       
        <constructor-arg index="1" type="com.ys.di.Student" ref="student_con"></constructor-arg>
    </bean>
    <bean id="student_con" class="com.ys.di.Student"></bean>

//利用 构造函数 给对象赋值
    @Test
    public void testConstrutor(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Person person = (Person) context.getBean("person_con");
        System.out.println(person.getPid());//1
    }