Spring的DI依赖注入（set注入）

环境 

普通属性

空值

引用对象

数组

List

Map

Set

Properties

综合代码

---

 

为什么叫set注入，是因为实际还是通过反射调用set方法注入，所以要注入的实体类字段要有相应的set方法

现在我们通过一个例子来说明一下

环境 

我们有学生类Student，班级类ClassRoom，科目类Subject，书类Book，我们要往学生类的属性注入值

学生类Student的代码

package com.lingaolu;

import java.util.*;

/**
 * @author 林高禄
 * @create 2020-11-03-9:19
 */
public class Student {
    private Long id;
    private String name;
    private String girlFriend;
    private ClassRoom classRoom;
    private String[] games;
    private List<Book> books;
    private Map<String,List<Book>> bookMap;
    private Set<Subject> subjectSet;
    private Properties properties;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getGirlFriend() {
        return girlFriend;
    }

    public void setGirlFriend(String girlFriend) {
        this.girlFriend = girlFriend;
    }

    public ClassRoom getClassRoom() {
        return classRoom;
    }

    public void setClassRoom(ClassRoom classRoom) {
        this.classRoom = classRoom;
    }

    public String[] getGames() {
        return games;
    }

    public void setGames(String[] games) {
        this.games = games;
    }

    public List<Book> getBooks() {
        return books;
    }

    public void setBooks(List<Book> books) {
        this.books = books;
    }

    public Map<String, List<Book>> getBookMap() {
        return bookMap;
    }

    public void setBookMap(Map<String, List<Book>> bookMap) {
        this.bookMap = bookMap;
    }

    public Set<Subject> getSubjectSet() {
        return subjectSet;
    }

    public void setSubjectSet(Set<Subject> subjectSet) {
        this.subjectSet = subjectSet;
    }

    public Properties getProperties() {
        return properties;
    }

    public void setProperties(Properties properties) {
        this.properties = properties;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", girlFriend='" + girlFriend + '\'' +
                ", classRoom=" + classRoom +
                ", games=" + Arrays.toString(games) +
                ", books=" + books +
                ", bookMap=" + bookMap +
                ", subjectSet=" + subjectSet +
                ", properties=" + properties +
                '}';
    }
}

 

班级类ClassRoom的代码

package com.lingaolu;

/**
 * @author 林高禄
 * @create 2020-11-04-8:53
 */
public class ClassRoom {

    private String name;

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "ClassRoom{" +
                "name='" + name + '\'' +
                '}';
    }
}

 

科目类Subject的代码

package com.lingaolu;

/**
 * @author 林高禄
 * @create 2020-11-04-9:00
 */
public class Subject {
    private String name;

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "Subject{" +
                "name='" + name + '\'' +
                '}';
    }
}

 

书类Book的代码

package com.lingaolu;

/**
 * @author 林高禄
 * @create 2020-11-04-8:52
 */
public class Book {
    private  String name;

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                '}';
    }
}

 

普通属性

name赋值林高禄 

空值

女朋友是null 

引用对象

数组

List

Map

Set

Properties

综合代码

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="book2" class="com.lingaolu.Book">
        <property name="name" value="我与小姨子的故事"/>
    </bean>
    <bean id="book3" class="com.lingaolu.Book">
        <property name="name" value="老师的特殊辅导"/>
    </bean>
    <bean id="classRoom" class="com.lingaolu.ClassRoom">
        <property name="name" value="材料103"/>
    </bean>
    <bean id="student" class="com.lingaolu.Student" >
        <property name="name" value="林高禄"/>
        <property name="girlFriend">
            <null/>
        </property>
        <property name="classRoom" ref="classRoom"/>
        <property name="games">
            <array>
                <value>LOL</value>
                <value>古墓丽影</value>
            </array>
        </property>
        <property name="books">
            <list>
                <bean id="book1" class="com.lingaolu.Book">
                    <property name="name" value="花季少年"/>
                </bean>
                <ref bean="book2"/>
            </list>
        </property>
        <property name="bookMap">
            <map>
                <entry key="老师系列">
                    <list>
                       <ref bean="book3"/>
                    </list>
                </entry>
                <entry key="空姐系列">
                    <list>
                        <bean class="com.lingaolu.Book">
                            <property name="name" value="我与副驾驶的故事"/>
                        </bean>
                    </list>
                </entry>
            </map>
        </property>
        <property name="subjectSet">
            <set>
                <bean class="com.lingaolu.Subject">
                    <property name="name" value="人体运动学"/>
                </bean>
            </set>
        </property>
        <property name="properties">
            <props>
                <prop key="age">17</prop>
            </props>
        </property>
    </bean>
</beans>

 

 测试打印结果