Spring笔记-ioc3 依赖注入 set所有类型注入 pc注入

依赖注入

• 依赖注入（Dependency Injection,DI）。
• 依赖 : 指Bean对象的创建依赖于容器 . Bean对象的依赖资源 .
• 注入 : 指Bean对象所依赖的资源 , 由容器来设置和装配 .

1 构造器注入

上一篇的

2 set注入 (重点)

要求被注入的属性 , 必须有set方法 , set方法的方法名由set + 属性首字母大写 , 如果属性是boolean类型, 没有set方法 , 是 is .

创建实体类:

package com.lx.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 + '\'' +
                '}';
    }
}

package com.lx.pojo;

import java.util.*;

public class Student {
    private String name;
    private Address address;
    private String[] books;
    private List<String> hobbys;
    private Map<String,String> card;
    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> getCard() {
        return card;
    }

    public void setCard(Map<String, String> card) {
        this.card = card;
    }

    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{" + '\n'+
                "name='" + name + '\'' +'\n'+
                 address+'\n'+
                "books=" + Arrays.toString(books) +'\n'+
                "hobbys=" + hobbys +'\n'+
                "card=" + card +'\n'+
                "games=" + games +'\n'+
                "wife='" + wife + '\'' +'\n'+
                "info=" + info +'\n'+
                '}';
    }
}

包含了所有的注入方式: 这里Student通过无参构造,无参不写默认创建的

在beans.xml中注册:

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


<!--    对Address类注册对象-->
    <bean id="address" class="com.lx.pojo.Address">
        <property name="address" value="希望以后可以去天津"/>
     </bean>
<!--对Student类注册对象 无参创建,通过property注入属性-->
    <bean id="student" class="com.lx.pojo.Student">

        <property name="name" value="lx"/>

<!--        bean注入  对象ref方式引入-->
        <property name="address" ref="address"/>

<!--        数组注入-->
        <property name="books" >
            <array>
                <value>语文</value>
                <value>数学</value>
                <value>英语</value>
                <value>物理</value>
                <value>化学</value>
                <value>生物</value>
            </array>
        </property>

<!--        List注入-->
        <property name="hobbys">
            <list>
                <value>女</value>
                <value>搬砖</value>
                <value>电影</value>
                <value>唱歌</value>
            </list>
        </property>

<!--        Map注入-->
        <property name="card">
            <map>
                <entry key="身份证" value="612516155812799264"/>
                <entry key="中行卡" value="546213254665413545"/>
            </map>
        </property>

<!--        set注入-->
        <property name="games">
            <set>
                <value>LOL</value>
                <value>王者荣耀</value>
                <value>pubg</value>
            </set>
        </property>

<!--        null注入-->
        <property name="wife">
            <null/>
        </property>

<!--        Properties-->
        <property name="info">
            <props>
                <prop key="学号" >1008039</prop>
                <prop key="姓名">lx</prop>
                <prop key="password">123456</prop>
            </props>
        </property>
    </bean>

</beans>

测试单元:

 @Test
    public void testStudent(){
        //set注入集合测试
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        Student student = (Student) context.getBean("student");
        System.out.println(student.toString());
    }

测试结果:

p / c 注入

引入条件
xmlns:p=“http://www.springframework.org/schema/p”
xmlns:c=“http://www.springframework.org/schema/c”

其实就是无参构造propetry 和有参构造的 construct-args 的简写
感觉没什么可说的 过

package com.lx.pojo;

public class User {
    private String name;
    private int age;

    public User() {
    }

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

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

    <!--p命名空间注入，可以直接注入属性的值：property-->
    <bean id="user" class="com.lx.pojo.User" p:age="18" p:name="lx" />


    <!--c命名空间注入，需要有参构造器,通过构造器注入：construct-args-->
     <bean id="user2" class="com.lx.pojo.User" c:age="20" c:name="wxy" />

@Test
    public void testPC(){
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("userbeans.xml");
        User userP = context.getBean("userP", User.class);
        System.out.println(userP.toString());
        System.out.println("===========");

        User userC = context.getBean("userC", User.class);
        System.out.println(userC.toString());

    }