Java Spring5学习之JdbcTemplate详解

2024-04-02 19:55

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一、JdbcTemplate

Spring 框架对 JDBC 进行封装，使用 JdbcTemplate 方便实现对数据库操作

二、实战

2.1 引入依赖


<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.24</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.6</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-orm -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.3.6</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>5.3.6</version>
        </dependency>

2.2 配置连接池


<!--引入外部属性文件 -->
    <context:property-placeholder
        location="classpath:jdbc.properties" />

    <!-- 数据库连接池 -->
    <bean id="dataSource"
        class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
        <property name="url" value="${prop.url}" />
        <property name="username" value="${prop.userName}" />
        <property name="password" value="${prop.password}" />
        <property name="driverClassName" value="${prop.driverClass}" />
    </bean>

2.3 配置JdbcTemplate 对象，注入 DataSource


 <!-- JdbcTemplate 对象 -->
    <bean id="jdbcTemplate"
        class="org.springframework.jdbc.core.JdbcTemplate">
        <!--注入 dataSource -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

2.4 扫描注解


<!-- 开启注解扫描 -->
    <context:component-scan
        base-package="cn.zj.aop.an"></context:component-scan>

2.5 创建 service 类，创建 dao 类，在 dao 注入 jdbcTemplate 对象


@Repository
public class UserDaoImpl implements UserDao {

    //注入 JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
}



@Service
public class UserService {

    // 注入 dao
    @Autowired
    private UserDao userDao;
    
}

三、操作(CRUD)

实体类


public class User {

    private String userId;
    private String username;
    private String ustatus;

    @Override
    public String toString() {
        return "User [userId=" + userId + ", username=" + username + ", ustatus=" + ustatus + "]";
    }

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getUstatus() {
        return ustatus;
    }

    public void setUstatus(String ustatus) {
        this.ustatus = ustatus;
    }

}

3.1 添加


service
//添加
    public void addUser(User user) {
        userDao.add(user);
    }
    
dao
@Override
    public void add(User user) {
        // 1 创建 sql 语句
        String sql = "insert into t_user values(?,?,?)";
        // 2 调用方法实现
        Object[] args = { user.getUserId(), user.getUsername(), user.getUstatus() };
        int update = jdbcTemplate.update(sql, args);
        System.out.println(update);

    }
    
测试

@Test
    public void test1() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        User user = new User();
        user.setUserId("1");
        user.setUsername("java");
        user.setUstatus("a");
        userService.addUser(user);
    }

结果

3.2 修改


service

//修改
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

dao
@Override
    public void updateUser(User user) {
        // TODO Auto-generated method stub
        String sql = "update t_user set username=?,ustatus=? where userId=?";
        // 2 调用方法实现
        Object[] args = { user.getUsername(), user.getUstatus() ,user.getUserId()};
        int update = jdbcTemplate.update(sql, args);
        System.out.println(update);
    }
测试
@Test
    public void test2() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        User user = new User();
        user.setUserId("1");
        user.setUsername("javaScrip");
        user.setUstatus("abc");
        userService.updateUser(user);
    }

3.3 删除


// 删除
    public void deleteUser(String id) {
        userDao.deleteUser(id);
    }


@Override
    public void deleteUser(String id) {
        String sql="delete from t_user where userId=?";
        int update=jdbcTemplate.update(sql, id);
        System.out.println(update);
    }


@Test
    public void test3() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        
        userService.deleteUser("1");
    }

四、查询

4.1 查询总记录数 jdbcTemplate.queryForObject


@Test
    public void test4() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        
        int count = userService.selectUserCount();
        System.out.println("数据库中共有记录:"+count);
    }


//查询记录数
    public int  selectUserCount() {
        return userDao.selectCount();
    }


    @Override
    public int selectCount() {
        String sql = "select count(0) from t_user";
        Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
        return count;
    }

4.2 查询返回对象


@Test
    public void test5() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        
        User user=userService.findUserInfo("1");
        System.out.println(user);
    }

//查询对象
    public User findUserInfo(String id) {
        // TODO Auto-generated method stub
        return userDao.findUserInfo(id);
    }

@Override
    public User findUserInfo(String id) {
        String sql = "select userId,username,ustatus from t_user where userId=?";
        User user = jdbcTemplate.queryForObject(sql, new
                BeanPropertyRowMapper<User>(User. class),id);
        return user;
    }

4.3 查询返回集合


@Test
    public void test6() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        
        List<User> list=userService.findAllUser();
        System.out.println(list);
    }

    //查询返回集合
    public List<User> findAllUser(){
        return userDao.findAllUser();
    }

@Override
    public List<User> findAllUser() {
        String sql = "select userId,username,ustatus from t_user";
        List<User> list = jdbcTemplate.query(sql, new
                BeanPropertyRowMapper<User>(User. class));
        return list;
    }

五、批量操作 jdbcTemplate.batchUpdate

5.1 添加


@Test
    public void test7() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        List<Object[]> list =  new ArrayList<>();
        Object[] o1 = { "11", "易语言", "中文"};
        Object[] o2 = { "12", "c++", "cc"};
        Object[] o3 = { "13", "MySQL", "数据库"};
        list.add(o1);
        list.add(o2);
        list.add(o3);
        userService.batchAdd(list);
    }

//批量添加
    public void batchAdd(List<Object[]> list){
        userDao.batchAdd(list);
    }

@Override
    public void batchAdd(List<Object[]> list) {
        String sql = "insert into t_user values(?,?,?)";
        int[] ints = jdbcTemplate.batchUpdate(sql, list);
        System.out.println(ints);
    }

5.2 修改


@Test
    public void test8() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        List<Object[]> list =  new ArrayList<>();
        Object[] o1 = {  "易语言易", "中文语言","11"};
        Object[] o2 = { "c++c", "ccccc","12"};
        Object[] o3 = {"MySQL+ORACle", "数据库数据", "13"};
        list.add(o1);
        list.add(o2);
        list.add(o3);
        userService.batchUpdate(list);
    }


    //批量修改
    public void batchUpdate(List<Object[]> list) {
        userDao.batchUpdate(list);
    }

@Override
    public void batchUpdate(List<Object[]> list) {
        String sql = "update t_user set username=?,ustatus=? where userId=?";
        int[] ints = jdbcTemplate.batchUpdate(sql, list);
        System.out.println(ints);
    }

5.3 删除


@Test
    public void test9() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
        UserService userService = context.getBean("userService", UserService.class);
        List<Object[]> list =  new ArrayList<>();
        Object[] o1 = { "11"};
        Object[] o2 = { "12"};
        Object[] o3 = { "13"};
        list.add(o1);
        list.add(o2);
        list.add(o3);
        userService.batchDelete(list);
    }

    //批量删除
    public void batchDelete(List<Object[]> list) {
        userDao.batchDelete(list);
    }

@Override
    public void batchDelete(List<Object[]> list) {
        String sql = "delete from t_user where userId=?";
        int[] ints = jdbcTemplate.batchUpdate(sql, list);
        System.out.println(ints);
    }

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