spring-IOC

springIOC

IOC创建对象方式

1. 通过无参构造方法创建

User.java （默认有无参构造方法）

public class User {
    private String name;

    public String getName() {
        return name;
    }

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

    public void show(){
        System.out.println("我的名字是："+name);
    }
}

beans.xml

<?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">

    <bean id="user" class="com.dingcd.pojo.User">
        <property name="name" value="dingcd"/>
    </bean>

</beans>

测试类

@Test
public void test1(){
    ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
    //在执行getBean的时候, user已经创建好了 , 通过无参构造
    User user = context.getBean("user", User.class);
    //调用对象的方法
    user.show();
}

结果可以发现，在调用show方法之前，User对象已经通过无参构造初始化了！

2. 通过有参构造方法创建

UserT.java

public class UserT {


    private String name;

    public UserT(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

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

    public void show(){
        System.out.println("我的名字是："+name);
    }
}

beans.xml

<?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">

    <!-- 第一种根据index参数下标设置 -->
    <bean id="userT" class="com.dingcd.pojo.UserT">
        <constructor-arg index="0" value="dingcd"/>
    </bean>

    <!-- 第二种根据参数名字设置 -->
    <bean id="userT" class="com.dingcd.pojo.UserT">
        <!-- name指参数名 -->
        <constructor-arg name="name" value="dingcd"/>
    </bean>

    <!-- 第三种根据参数类型设置 -->
    <bean id="userT" class="com.dingcd.pojo.UserT">
        <constructor-arg type="java.lang.String" value="dingcd"/>
    </bean>

</beans>

测试类

@Test
public void test2(){
    ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
    UserT user =  context.getBean("userT",UserT.class);
    user.show();
}

3. 别名

alias 设置别名 , 为bean设置别名 , 可以设置多个别名

<!--设置别名：在获取Bean的时候可以使用别名获取-->
<alias name="userT" alias="userNew"/>

4.import

团队的合作通过import来实现 .

<import resource="{path}/beans.xml"/>

IOC注入方式

测试pojo类 :

Address.java

public class Address {
 
     private String address;
 
     public String getAddress() {
         return address;
    }
 
     public void setAddress(String address) {
         this.address = address;
    }
 }

Student.java

package com.dingcd.pojo;
 
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
 
 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 void setName(String name) {
         this.name = name;
    }
 
     public void setAddress(Address address) {
         this.address = address;
    }
 
     public void setBooks(String[] books) {
         this.books = books;
    }
 
     public void setHobbys(List<String> hobbys) {
         this.hobbys = hobbys;
    }
 
     public void setCard(Map<String, String> card) {
         this.card = card;
    }
 
     public void setGames(Set<String> games) {
         this.games = games;
    }
 
     public void setWife(String wife) {
         this.wife = wife;
    }
 
     public void setInfo(Properties info) {
         this.info = info;
    }
 
     public void show(){
         System.out.println("name="+ name
                 + ",address="+ address.getAddress()
                 + ",books="
        );
         for (String book:books){
             System.out.print("<<"+book+">>\t");
        }
         System.out.println("\n爱好:"+hobbys);
 
         System.out.println("card:"+card);
 
         System.out.println("games:"+games);
 
         System.out.println("wife:"+wife);
 
         System.out.println("info:"+info);
 
    }
 }

1.常量注入

<bean id="student" class="com.dingcd.pojo.Student">
    <property name="name" value="小明"/>
</bean>

2.Bean注入

<bean id="addr" class="com.dingcd.pojo.Address">
     <property name="address" value="重庆"/>
 </bean>
 
 <bean id="student" class="com.dingcd.pojo.Student">
     <property name="name" value="小明"/>
     <property name="address" ref="addr"/>
 </bean>

3.数组注入

<bean id="student" class="com.dingcd.pojo.Student">
     <property name="name" value="小明"/>
     <property name="address" ref="addr"/>
     <property name="books">
         <array>
             <value>西游记</value>
             <value>红楼梦</value>
             <value>水浒传</value>
         </array>
     </property>
 </bean>

4.List注入

<property name="hobbys">
     <list>
         <value>听歌</value>
         <value>看电影</value>
         <value>爬山</value>
     </list>
 </property>

5.Map注入

<property name="card">
     <map>
         <entry key="中国邮政" value="456456456465456"/>
         <entry key="建设" value="1456682255511"/>
     </map>
 </property>

6.set注入

<property name="games">
     <set>
         <value>LOL</value>
         <value>BOB</value>
         <value>COC</value>
     </set>
 </property>

7.Null注入

<property name="wife"><null/></property>

8.Properties注入

<property name="info">
     <props>
         <prop key="学号">20190604</prop>
         <prop key="性别">男</prop>
         <prop key="姓名">小明</prop>
     </props>
 </property>

9.p命名和c命名注入

User.java ：【注意：这里没有有参构造器！】

public class User {
     private String name;
     private int age;
 
     public void setName(String name) {
         this.name = name;
    }
 
     public void setAge(int age) {
         this.age = age;
    }
 
     @Override
     public String toString() {
         return "User{" +
                 "name='" + name + '\'' +
                 ", age=" + age +
                 '}';
    }
 }

1、P命名空间注入 : 需要在头文件中加入约束文件

 导入约束 : xmlns:p="http://www.springframework.org/schema/p"
 
 <!--P(属性: properties)命名空间 , 属性依然要设置set方法-->
 <bean id="user" class="com.dingcd.pojo.User" p:name="达达" p:age="18"/>

2、c 命名空间注入 : 需要在头文件中加入约束文件

 导入约束 : xmlns:c="http://www.springframework.org/schema/c"
 <!--C(构造: Constructor)命名空间 , 属性依然要设置set方法-->
 <bean id="user" class="com.dingcd.pojo.User" c:name="达达" c:age="18"/>

发现问题：爆红了，刚才我们没有写有参构造！

解决：把有参构造器加上，这里也能知道，c 就是所谓的构造器注入！

测试代码：

@Test
 public void test02(){
     ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
     User user = context.getBean("user",User.class);
     System.out.println(user);
 }

posted @ 2021-08-01 21:51 达1024 阅读(30) 评论(0) 收藏举报

刷新页面返回顶部

达1024