Spring框架SSM之IOC詳解

更新時(shí)間：2025年11月10日 09:50:35 作者：北城以北Iris

本文介紹了Spring框架中IOC（控制反轉(zhuǎn)/依賴注入）的兩種實(shí)現(xiàn)方式,每種方式結(jié)合實(shí)例代碼給大家介紹的非常詳細(xì),感興趣的朋友一起看看吧

Spring框架之IOC

1.Spring框架搭建

在pom文件中引入jar包

<properties>
    <spring.version>4.0.2.RELEASE</spring.version>
</properties>
<!-- spring框架包 -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-oxm</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-expression</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-orm</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.8</version>
</dependency>

2.IOC(控制反轉(zhuǎn)/依賴注入)

將程序的控制權(quán)從代碼本身轉(zhuǎn)移到外部容器

組件化的思想：分離關(guān)注點(diǎn)，使用接口，不再關(guān)注實(shí)現(xiàn)

依賴的注入：將組件的構(gòu)建和使用分開

2.1在配置文件中進(jìn)行控制反轉(zhuǎn)和依賴注入

dao層

/**
 * 顯示信息
 */
public interface UserDao {
    public void show() ;
}
public class UserDaoImpl implements UserDao {
    @Override
    public void show() {
        System.out.println("輸出UserDaoImpl信息");
    }
}

service層

public interface UserService {
    /**
     * 顯示信息
     */
    public void show() ;
}
public class UserServiceImpl implements UserService {
    @Setter
    private UserDao userDao;
    @Override
    public void show() {
        userDao.show();
    }
}

在resources文件夾下創(chuàng)建一個(gè)spring.xml配置文件

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="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">
</beans>

xml配置文件

<!--    配置userDao bean-->
<bean  id="userDao" class="com.hz.dao.impl.UserDaoImpl"></bean>
<bean id="userService" class="com.hz.service.impl.UserServiceImpl">
<!--        配置userDao屬性，ref引用userDao bean -->
	<property name="userDao" ref="userDao"></property>
</bean>

讀取配置文件并運(yùn)行

//使用ClassPathXmlApplicationContext讀取配置文件
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
UserService userService =(UserService) context.getBean("userService");
userService.show();

2.2使用注解的形式實(shí)現(xiàn)

@Component：實(shí)現(xiàn)Bean組件的定義

@Repository([實(shí)例化名稱]) ：用于標(biāo)注DAO類默認(rèn)使用當(dāng)前類的類名（首字母小寫）作為bean的別名

@Service([實(shí)例化名稱]) ：用于標(biāo)注Service業(yè)務(wù)類默認(rèn)使用當(dāng)前類的類名（首字母小寫）作為bean的別名

@Autowired+@Quali?er(“userDao”)等價(jià)于@Resource(name = “userDao”)

dao層

/**
 * 顯示信息
 */
public interface UserDao {
 /**
   * 刪除學(xué)生
   * @param id
   */
  public int delStudent(Integer id);
}
@Repository
public class UserDaoImpl implements UserDao {
       @Override
    public int delStudent(Integer id) {
        System.out.println("刪除id為"+id+"的學(xué)生");
        return 0;
    }
}

service層

public interface UserService {
      /**
     * 刪除學(xué)生
     * @param id
     */
    public  int delStudent(Integer id);
}
@Service
public class UserServiceImpl implements UserService {
  //@Resource(name = "userDaoImpl")
    @Autowired
 //@Qualifier("userDaoImpl")
    private UserDao userDao;
    @Override
    public int delStudent(Integer id) {
        userDao.delStudent(id);
       return  100;
    }
}

注：JDK17把@Resource廢除，如果需要使用此注解需導(dǎo)入jar包

<dependency>
      <groupId>javax.annotation</groupId>
      <artifactId>javax.annotation-api</artifactId>
      <version>1.2</version>
</dependency>

在配置文件中開啟注解

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="
       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">
      <!--    配置組件掃描，掃描com.hz.dao和com.hz.service和com.hz.aop包下的類 -->
    <context:component-scan base-package="com.hz.dao,com.hz.service"/>
</beans>

讀取配置文件

//使用ClassPathXmlApplicationContext讀取配置文件
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
//因?yàn)锧Repository默認(rèn)使用當(dāng)前類的簡單類名（首字母小寫）作為bean的別名，所以使用getBean("userServiceImpl")獲取對(duì)象
UserService userService =(UserService) context.getBean("userServiceImpl");
userService.delStudent(1001);