DI依赖注入环境

1.构造器注入

上一章节已经说过了：

   

<?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/beanshttps://www.springframework.org/schema/beans/spring-beans.xsd"><!-- 有参构造的注入   -->
<!-- 第一种方式： 下标赋值  -->
<!--    <bean id="user" class="com.kuang.pojo.User">-->
<!--        <constructor-arg index="0" value="基基基基基基"/>-->
<!--    </bean>--><!-- 第二种方式：类型赋值，最好别用   -->
<!--    <bean id="user" class="com.kuang.pojo.User">-->
<!--        <constructor-arg type="java.lang.String" value="鸡哥"/>-->
<!--    </bean>--><bean id="userT" class="com.kuang.pojo.User"/>
<!--  第三种方式:直接通过参数名来设置  --><bean id="user" class="com.kuang.pojo.User"><constructor-arg name="name" value="鸡哥"/></bean>
<alias name="user" alias="sada"/></beans>

2.通过set方式注入【重点】

p对属性 c对构造器。。。

• 依赖注入：Set注入！

1.  依赖：bean对象的创建依赖于容器！
2.  注入：bean对象中的所有属性，由容器来注入！

【环境搭建】

1.复杂类型

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

1. 2 真实对象     

package com.kuang.pojo;import java.util.*;public class Student {private String name;private Address address;private String[] books;private List<String> hobbies;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> getHobbies() {return hobbies;}public void setHobbies(List<String> hobbies) {this.hobbies = hobbies;}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;}@Overridepublic String toString() {return "Student{" +"name='" + name + '\'' +", address=" + address +", books=" + Arrays.toString(books) +", hobbies=" + hobbies +", card=" + card +", games=" + games +", wife='" + wife + '\'' +", info=" + info +'}';}
}

1.3  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="student" class="com.kuang.pojo.Student">
<!-- 第一种方式 ：普通值注入，value   --><property name="name" value="基基"/>
</bean></beans>

DI是实现控制反转的一种设计模式，依赖注入就是将实例变量传入到一个对象中去

  

1.4测试类

package mytest;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.getName());}
}

完善注入信息

<?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="address" class="com.kuang.pojo.Address"><property name="address" value="广西省"/></bean><bean id="student" class="com.kuang.pojo.Student">
<!-- 第一种方式 ：普通值注入，value   --><property name="name" value="基基"/>
<!--  第二种方式 : Bean注入， ref      --><property name="address" ref="address"/>
<!--  数组注入      --><property name="books"><array><value>红楼梦</value><value>水浒传</value><value>三国演义</value><value>西游记</value></array></property>
<!--   集合注入     --><property name="hobbies"><list><value>听歌</value><value>敲代码</value><value>看电影</value></list></property>
<!--   Map注入     --><property name="card"><map><entry key="身份证" value="21312312312131"/><entry key="银行卡" value="42121312321312123"/></map></property>
<!--    Set注入    --><property name="games"><set><value>LOL</value><value>COC</value><value>BOB</value></set></property>
<!--    null注入    --><property name="wife"><null/></property><!--   Properties类注入     --><property name="info"><props><prop key="driver">com.mysql.jdbc</prop><prop key="url">localhost:3306/?</prop><prop key="username">root</prop><prop key="password">2001</prop></props></property>
</bean></beans>

P命名空空间注入

  对应着Property   ：Set注入

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd">
<!--  P命名空间注入 Set方法注入  Properties  --><bean id="user" class="com.kuang.pojo.User" p:name="秦疆" p:age="19" p:sponse-ref="user1"/><bean id="user1" class="com.kuang.pojo.User" p:name="花" p:age="21" /></beans>

 @Testpublic void test(){ApplicationContext context = new ClassPathXmlApplicationContext("Userbeans.xml");User user = context.getBean("user", User.class);System.out.println(user);}

C命名空空间注入

  对应着construct   ：构造器注入

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:c="http://www.springframework.org/schema/c"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd">
<!--  C命名空间注入:construct-args  --><bean id="user2" class="com.kuang.pojo.User" c:age="18" c:name="狂神" c:sponse-ref="user1"/><bean id="user1" class="com.kuang.pojo.User" p:name="花" p:age="21" />
</beans>

   @Testpublic void test(){ApplicationContext context = new ClassPathXmlApplicationContext("Userbeans1.xml");User user = context.getBean("user2", User.class);System.out.println(user);}

3.拓展方式注入

我们可以使用P命名空间和C命名空间进行注入

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:c="http://www.springframework.org/schema/c"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd">
<!--  C命名空间注入:construct-args  --><bean id="user2" class="com.kuang.pojo.User" c:age="18" c:name="狂神" c:sponse-ref="user1"/><bean id="user1" class="com.kuang.pojo.User" p:name="花" p:age="21" />
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd">
<!--  P命名空间注入 property  set 方式注入 --><bean id="user" class="com.kuang.pojo.User" p:name="秦疆" p:age="19" p:sponse-ref="user1"/><bean id="user1" class="com.kuang.pojo.User" p:name="花" p:age="21" /></beans>

p命名和C命名不能直接使用，需要导入xml约束以后才能使用

xmlns:p="http://www.springframework.org/schema/p"

xmlns:c="http://www.springframework.org/schema/c"