Spring：IOC依赖注入

    在Spring中实现依赖注入有两种方式&＃xff0c;分别是通过注解的方式和通过xml的方式&＃xff0c;以下案例是在Spring3.x版本进行讲解。

一、使用注解的方式实现IOC

1.1、导入Spring类库

1.2、编写数据访问层DAO

这里面只是提供了一个空的类&＃xff0c;我们的目的是为了测试在Service层中是否可以成功的将这个Dao类注入。通过&＃64;Repository注解来标注Dao

package com.dao;import org.springframework.stereotype.Repository;/*** * 配置DAO* * &＃64;author thinkpad**/
&＃64;Repository("userDao")
public class UserDao {}


1.3、编写服务层Service

我们通过&＃64;Service注解来标注Service

package com.service;import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.annotation.Resource;import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;import com.dao.UserDao;/*** 配置Service* * &＃64;author thinkpad**/
&＃64;Service("userService")
&＃64;Scope("singleton") //单实例
//&＃64;Scope("prototype") //多实例
public class UserService {&＃64;Value("用户服务")private String info;// &＃64;Autowired// &＃64;Qualifier("userDao")&＃64;Resource(name &＃61; "userDao")private UserDao dao;/*** 初始化注解*/&＃64;PostConstructpublic void setup() {System.out.println("对象初始化");}/*** 销毁注解*/&＃64;PreDestroypublic void teardown() {System.out.println("对象销毁");}&＃64;Overridepublic String toString() {return "info&＃xff1a;" &＃43; this.info &＃43; "&＃xff0c;dao&＃xff1a;" &＃43; this.dao;}
}


1.4、在applicationContext.xml中配置注解扫描


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


1.5、测试

package test;import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.service.UserService;public class JTest {&＃64;Testpublic void test1() {ClassPathXmlApplicationContext ctx &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");UserService en &＃61; (UserService) ctx.getBean("userService");System.out.println(en);UserService en2 &＃61; (UserService) ctx.getBean("userService");System.out.println(en.equals(en2));ctx.close();}}


1.6、运行结果

二、使用XML的方式实现IOC

1.1、导入Spring类库

1.2、要注入的实体对象

package test.entity;public class EntityInner {private String name;public void setName(String name) {this.name &＃61; name;}public String getName() {return name;}&＃64;Overridepublic String toString() {return "Inner姓名&＃xff1a;" &＃43; this.name;}}package test.entity;public class Entity1 {private String name;public Entity1(String name) {this.name &＃61; name;}&＃64;Overridepublic String toString() {return "姓名&＃xff1a;" &＃43; this.name;}
}package test.entity;public class Entity2 {private String name;public void setName(String name) {this.name &＃61; name;}&＃64;Overridepublic String toString() {return "姓名&＃xff1a;" &＃43; this.name;}
}package test.entity;public class Entity3 {private String name;private EntityInner inner;public void setName(String name) {this.name &＃61; name;}public void setInner(EntityInner inner) {this.inner &＃61; inner;}&＃64;Overridepublic String toString() {return "姓名&＃xff1a;"&＃43;this.name &＃43; "&＃xff0c;inner&＃xff1a;"&＃43;this.inner.toString();}
}package test.entity;import java.util.List;
import java.util.Map;
import java.util.Properties;public class Entity4 {private List cities;private Map persons;private Properties users;public List getCities() {return cities;}public void setCities(List cities) {this.cities &＃61; cities;}public Map getPersons() {return persons;}public void setPersons(Map persons) {this.persons &＃61; persons;}public Properties getUsers() {return users;}public void setUsers(Properties users) {this.users &＃61; users;}}


1.3、在applicationContext.xml中配置注解扫描

applicationContext.xml

applicationContext2.xml


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1.4、测试

package test;import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import test.entity.Entity1;
import test.entity.Entity2;
import test.entity.Entity3;
import test.entity.Entity4;public class JTest {/*** 通过Setter方法注入依赖对象*/&＃64;Testpublic void test1() {ApplicationContext cxt &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");Entity1 en &＃61; (Entity1) cxt.getBean("entity2");System.out.println(en.toString());}/*** 通过构造器注入依赖对象*/&＃64;Testpublic void test1_1() {ApplicationContext cxt &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");Entity2 en &＃61; (Entity2) cxt.getBean("entity1");System.out.println(en.toString());}/*** 注入实体*/&＃64;Testpublic void test2() {ApplicationContext cxt &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");Entity3 en &＃61; (Entity3) cxt.getBean("entity5");System.out.println(en.toString());}/*** 注入集合*/&＃64;Testpublic void test3() {ApplicationContext cxt &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");Entity4 en &＃61; (Entity4) cxt.getBean("entity6");System.out.println(en.getCities());System.out.println(en.getPersons());System.out.println(en.getUsers());}
}

四、源代码

Spring通过注解实现IOC

Spring通过xml实现IOC