Spring学习二-使用 Spring 的 IOC实现 CRUD 功能

程序员文章站 2022-04-23 16:02:13

...

1、使用 Spring 的 IOC 实现 CRUD

IOC 的 xml 配置实现

1.1、POM依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.wmding.spring</groupId>
    <artifactId>com.wmding.spring</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!--spring的依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
        </dependency>

        <!--dbutils操作数据库-->
        <dependency>
            <groupId>commons-dbutils</groupId>
            <artifactId>commons-dbutils</artifactId>
            <version>1.4</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
        <!--JDBC连接池-->
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
        </dependency>
        <!--测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

</project>

1.2、持久层实现

实现对数据库的查询，首先要创建数据库

 CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'id',
  `age` int DEFAULT NULL COMMENT '年龄',
  `name` varchar(100) DEFAULT NULL COMMENT '姓名',
   PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

操作数据库

public class UserDao {

    private QueryRunner runner;
		
    public void setRunner(QueryRunner runner) {
        this.runner = runner;
    }

    public int saveUser(User user) {
        try {
            return runner.update("insert into user(name,age) values(?,?)",user.getName(),user.getAge());
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return -1;
    }

    public List<User> list() {
        try {
            return runner.query("select * from user",new BeanListHandler<User>(User.class));
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    public int deleteUser(Integer userId) {
        try {
            return runner.update("delete from user where id=?",userId);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return -1;
    }

    public User getUserById(Integer id){
        try {
            return runner.query("select * from user where id = ?",new BeanHandler<User>(User.class),id);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

}

1.3、业务层实现

1.3.1、业务接口

public interface UserService {

    int saveUser(User user);

    List<User> list();

    int deleteUser(Integer userId);

    User getUserById(Integer id);
}

1.3.2、接口实现

public class UserServiceImpl implements UserService {

    private UserDao userDao;

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    public int saveUser(User user) {
        return userDao.saveUser(user);
    }

    public List<User> list() {
        return userDao.list();
    }

    public int deleteUser(Integer userId) {
        return userDao.deleteUser(userId);
    }

    public User getUserById(Integer id) {
        return userDao.getUserById(id);
    }
}

1.4、IOC 配置（bean.xml）

bean.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"
       xmlns:p="http://www.springframework.org/schema/p" 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 https://www.springframework.org/schema/context/spring-context.xsd">
  
    <bean id="userService" class="com.wmding.spring.serivce.impl.UserServiceImpl">
        <property name="userDao" ref="userDao"/>
    </bean>

    <bean id="userDao" class="com.wmding.spring.dao.UserDao">
        <property name="runner" ref="runner"/>
    </bean>
		
  	<!--配置QueryRunner-->
    <bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
      	<!--注入数据源-->
        <constructor-arg name="ds" ref="dataSource"/>
    </bean>

  	<!-- 配置数据源 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
      	<!--连接数据库的必备信息-->
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/spring?useUnicode=true&amp;characterEncoding=utf8&amp;autoReconnect=true&amp;useSSL=false&amp;serverTimezone=UTC"/>
        <property name="user" value="root"/>
        <property name="password" value="root"/>
    </bean>

</beans>

1.5、测试类

public class UserTest {

    @Test
    public void saveUser(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        UserService userService = (UserService) ac.getBean("userService");
        User user = new User();
        user.setAge(10);
        user.setName("1jfeklf");
        int i = userService.saveUser(user);
        System.out.println(i);
    }

    @Test
    public void list(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        UserService userService = (UserService) ac.getBean("userService");
        List<User> list = userService.list();

        for (User user : list) {
            System.out.println(user);
        }
    }

    @Test
    public void deleteUser(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        UserService userService = (UserService) ac.getBean("userService");
        userService.deleteUser(1);
    }


    @Test
    public void getUserById(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        UserService userService = (UserService) ac.getBean("userService");
        User user = userService.getUserById(1);
        System.out.println(user);
    }
}

2、基于注解的 IOC 配置

使用注解的方式实现

2.1、POM依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.wmding.spring</groupId>
    <artifactId>com.wmding.spring</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!--spring的依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
        </dependency>

        <!--dbutils操作数据库-->
        <dependency>
            <groupId>commons-dbutils</groupId>
            <artifactId>commons-dbutils</artifactId>
            <version>1.4</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
        <!--JDBC连接池-->
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
        </dependency>
        <!--测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

</project>

2.2、持久层实现

使用了注解 @Repository，将 userDao 注入到 Spring 的容器中

@Repository("userDao")
public class UserDao {

    @Autowired
    private QueryRunner runner;


    public int saveUser(User user) {
        try {
            return runner.update("insert into user(name,age) values(?,?)",user.getName(),user.getAge());
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return -1;
    }

    public List<User> list() {
        try {
            return runner.query("select * from user",new BeanListHandler<User>(User.class));
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    public int deleteUser(Integer userId) {
        try {
            return runner.update("delete from user where id=?",userId);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return -1;
    }

    public User getUserById(Integer id){
        try {
            return runner.query("select * from user where id = ?",new BeanHandler<User>(User.class),id);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

}

2.3、业务层实现

2.3.1、业务接口

public interface UserService {

    int saveUser(User user);

    List<User> list();

    int deleteUser(Integer userId);

    User getUserById(Integer id);
}

2.3.2、业务实现

@Service("userService")
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    public int saveUser(User user) {
        return userDao.saveUser(user);
    }

    public List<User> list() {
        return userDao.list();
    }

    public int deleteUser(Integer userId) {
        return userDao.deleteUser(userId);
    }

    public User getUserById(Integer id) {
        return userDao.getUserById(id);
    }
}

2.4、使用注解代替bean.xml

/**
 * @author 明月
 * @version 1.0
 * @date 2020-04-20 22:40
 * @description:
 *
 * 该类是一个配置类，它的作用是和bean.xml是一样的
 *
 * @Configuration
 *  作用：指定当前类是一个配置类
 * @ComponentScan
 *  作用：用于通过注解指定spring在创建容器时要扫描的包
 *  属性：
 *      value 和 basePackage 的作用一样
 *      等同于bean.xml中的
 *      <context:component-scan base-package="com.wmding.spring"/>
 * @Bean
 *  作用：用于把当前方法的返回值作为 bean 对象存入到 spring 的容器中
 *  属性：
 *      name 和 value 的作用一样，指定 bean的 id；如果不写，默认是当前方法的名称
 *
 * @Import
 *  作用：用于引入其他的配置类
 *  属性：
 *   value：用于指定引入其他配置类的字节码
 *
 * @PropertySource
 *  作用：用于指定 properties 文件的位置
 *  属性：
 *      value：指定文件的名称和路径
 *      	classpath 表示类路径下
 *
 */
@Configuration
@ComponentScan(value = "com.wmding.spring")
@Import(value = JdbcConfig.class)
public class SpringConfig {
    
}

// 引入配置文件
@PropertySource(value = "classpath:jdbc.properties")
public class JdbcConfig {

    /**
     * <bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
     * <constructor-arg name="ds" ref="dataSource"/>
     * </bean>
     *
     * <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
     * <property name="driverClass" value="com.mysql.jdbc.Driver"/>
     * <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/spring?useUnicode=true&amp;characterEncoding=utf8&amp;autoReconnect=true&amp;useSSL=false&amp;serverTimezone=UTC"/>
     * <property name="user" value="root"/>
     * <property name="password" value="root"/>
     * </bean>
     */
    
    @Value("${jdbc.driver}")
    private String driver;

    @Value("${jdbc.url}")
    private String url;


    @Value("${jdbc.username}")
    private String username;


    @Value("${jdbc.password}")
    private String password;


    @Bean(value = "runner")
    //@Scope(value = "prototype")
    public QueryRunner runner(DataSource dataSource) {
        return new QueryRunner(dataSource);
    }

    @Bean(value = "dataSource")
    public DataSource dataSource() {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        try {
            comboPooledDataSource.setDriverClass(driver);
            comboPooledDataSource.setJdbcUrl(url);
            comboPooledDataSource.setUser(username);
            comboPooledDataSource.setPassword(password);
        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }

        return comboPooledDataSource;
    }
}

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring?useUnicode=true&amp;characterEncoding=utf8&amp;autoReconnect=true&amp;useSSL=false&amp;serverTimezone=UTC
jdbc.username=root
jdbc.password=root

2.5、测试类

public class UserTest {

    @Test
    public void saveUser(){
        ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService = (UserService) ac.getBean("userService");
        User user = new User();
        user.setAge(20);
        user.setName("王明2");
        int i = userService.saveUser(user);
        System.out.println(i);
    }

    @Test
    public void list(){
        ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService = (UserService) ac.getBean("userService");
        List<User> list = userService.list();

        for (User user : list) {
            System.out.println(user);
        }
    }

    @Test
    public void deleteUser(){
        ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService = (UserService) ac.getBean("userService");
        userService.deleteUser(1);
    }


    @Test
    public void getUserById(){
        ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService = (UserService) ac.getBean("userService");
        User user = userService.getUserById(1);
        System.out.println(user);
    }
}

3、Spring 整合 Junit

之前的测试类中，需要使用如下代码，来实现从spring 容器中取bean。

ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfig.class);
UserService userService = (UserService) ac.getBean("userService");

但是每个测试方法中都有重复代码，spring 已经提供了整合 junit 的方法。

3.1、添加依赖

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-test</artifactId>
  <version>5.2.2.RELEASE</version>
</dependency>

3.2、测试类修改

Spring 整合 junit 的配置

1、导入Spring整合Junit的jar
2、使用Junit 提供的一个注解，把原来的 main 方法替换了，替换成Spring提供的

@RunWith
3、告知Spring运行器，Spring和IOC创建是基于xml的还是注解的，并说明位置

@ContextConfiguation

locations: 指定xml文件的位置，加上 classpath 关键字，表示在类路径下

classes: 指定注解类所在的位置

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class UserTest2 {

    @Autowired
    private UserService userService;

    @Test
    public void saveUser(){
        User user = new User();
        user.setAge(20);
        user.setName("王明2");
        int i = userService.saveUser(user);
        System.out.println(i);
    }

    @Test
    public void list(){
        List<User> list = userService.list();

        for (User user : list) {
            System.out.println(user);
        }
    }

    @Test
    public void deleteUser(){
        userService.deleteUser(1);
    }

    @Test
    public void getUserById(){
        User user = userService.getUserById(1);
        System.out.println(user);
    }
}