Java Spring5学习之JdbcTemplate详解

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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