不同类型变量的依赖注入(Set注入)

在Spring中，依赖注入有三种方式：构造器注入、Set注入、拓展注入，其中Set注入是重点，接下来将详细介绍不同类型变量使用Set注入如何实现。

1、配置环境：

• 以下软件环境为：IntelliJ IDEA
• 建立一个"spring-03-di"模块，在该模块下建一个"con.kuang.pojo"包
• 在包下建两个实体类：Address与Student

其中，Address类代码如下：

package com.kuang.pojo;

public class Address {
    private String address;

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

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

Student类代码如下：

package com.kuang.pojo;

import java.util.*;

public class Student {
    private String name;
    private Address address;
    private String[] books;
    private List<String> hobbys;
    private Map<String,String> cards;
    private Set<String> games;
    private String wife;
    private Properties info;

    public String getName() {
        return name;
    }

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

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public String[] getBooks() {
        return books;
    }

    public void setBooks(String[] books) {
        this.books = books;
    }

    public List<String> getHobbys() {
        return hobbys;
    }

    public void setHobbys(List<String> hobbys) {
        this.hobbys = hobbys;
    }

    public Map<String, String> getCards() {
        return cards;
    }

    public void setCards(Map<String, String> cards) {
        this.cards = cards;
    }

    public Set<String> getGames() {
        return games;
    }

    public void setGames(Set<String> games) {
        this.games = games;
    }

    public String getWife() {
        return wife;
    }

    public void setWife(String wife) {
        this.wife = wife;
    }

    public Properties getInfo() {
        return info;
    }

    public void setInfo(Properties info) {
        this.info = info;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", address=" + address.toString() +
                ", books=" + Arrays.toString(books) +
                ", hobbys=" + hobbys +
                ", cards=" + cards +
                ", games=" + games +
                ", wife='" + wife + '\'' +
                ", info=" + info +
                '}';
    }
}

2、建立一个beans.xml文件，各种类型变量注入方式：基本类型、引用类型、数组、List、Map、Set、null、Properties

<?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="address" class="com.kuang.pojo.Address">
        <property name="address" value="南京"/>
    </bean>
    <bean id="student" class="com.kuang.pojo.Student">
        <!--基本类型-->
        <property name="name" value="陈大发" />
        <!--引用类型-->
        <property name="address" ref="address" />
        <!--数组-->
        <property name="books">
            <array>
                <value>语文</value>
                <value>数学</value>
                <value>英语</value>
            </array>
        </property>
        <!--List-->
        <property name="hobbys">
            <list>
                <value>听歌</value>
                <value>跑步</value>
                <value>爬山</value>
            </list>
        </property>
        <!--Map-->
        <property name="cards">
            <map>
                <entry key="身份证" value="23262119880324774"></entry>
                <entry key="银行卡" value="622223262119880324"></entry>
            </map>
        </property>
        <!--Set-->
        <property name="games">
            <set>
                <value>LOL</value>
                <value>斗地主</value>
                <value>掼蛋</value>
            </set>
        </property>
        <!--null-->
        <property name="wife">
            <null/>
        </property>
        <!--Properties-->
        <property name="info">
            <props>
                <prop key="学号">1190088</prop>
                <prop key="性别">女</prop>
                <prop key="民族">汉族</prop>
            </props>
        </property>
    </bean>


</beans>

3、建立一个测试类MyTest，代码如下：

import com.kuang.pojo.Student;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
       
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        Student student = (Student) context.getBean("student");
        System.out.println(student.toString());
    }
}

输出为：

        * Student{
        * name='陈大发',
        * address=Address{address='南京'},
        * books=[语文, 数学, 英语],
        * hobbys=[听歌, 跑步, 爬山],
        * cards={身份证=23262119880324774, 银行卡=622223262119880324},
        * games=[LOL, 斗地主, 掼蛋],
        * wife='null',
        * info={学号=1190088, 性别=女, 民族=汉族}}