六、依赖注入DI
1.构造器注入
前面的hello就是构造器注入
2.Set方式注入【重点】
- 依赖注入：Set注入！
- 依赖：bean对象的创建依赖于容器
- 注入：bean对象中的所有属性，由容器来注入
2.1【环境搭建】
1.复杂类型
package com.hxl.pojo; public class Address { private String address; public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } }
2.真实测试对象
package com.hxl.pojo; import java.util.*; public class Student { private String name; //引用类型，到时候用ref赋值 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{" + "name='" + name + '\'' + ", address=" + address + ", books=" + Arrays.toString(books) + ", hobbys=" + hobbys + ", card=" + card + ", games=" + games + ", wife='" + wife + '\'' + ", info=" + info + '}'; } }
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"> <!--第一种：普通值注入：value--> <bean id="student" class="com.hxl.pojo.Student"> <property name="name" value="王木木"/> </bean> </beans>
4.测试类
import com.hxl.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()); } }
2.2 示例
<?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.hxl.pojo.Address"/> <bean id="student" class="com.hxl.pojo.Student"> <!--第一种：普通值注入：value--> <property name="name" value="王木木"/> <!--第二种，Bean注入：ref--> <property name="address" ref="address"/> <!--第三种，数组注入--> <property name="books"> <array> <value>红楼梦</value> <value>水浒传</value> </array> </property> <!--第四种：List注入--> <property name="hobbys"> <list> <value>谈恋爱</value> <value>敲代码</value> </list> </property> <!--第五种：Map--> <property name="card"> <map> <entry key="身份证" value="1254482515165451X"/> <entry key="银行卡" value="1549413214151515485"/> </map> </property> <!--第六种：Set--> <property name="games"> <set> <value>LOL</value> <value>王者荣耀</value> </set> </property> <!--第七种：NULL--> <property name="wife"> <null/> </property> <!--第八种：Properties--> <property name="info"> <props> <prop key="学号">yj2021</prop> <prop key="姓名">王木木</prop> </props> </property> </bean> </beans>
import com.hxl.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()); /* * Student{name='王木木', address=Address{address='null'}, books=[红楼梦, 水浒传], hobbys=[谈恋爱, 敲代码], * card={身份证=1254482515165451X, 银行卡=1549413214151515485}, games=[LOL, 王者荣耀], wife='null', * info={学号=yj2021, 姓名=王木木}} * */ } }
运行之前记得在address中加入toString方法，以及在Student中的toString中加入address.toString()
