Spring中的jdbcTemplate操作

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Spring中的jdbcTemplate操作

准备工作

1.设置数据库信息

DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("com.mysql.jdbc.Driver");
dataSource.setUrl("jdbc:mysql://localhost:3306/ssm");
dataSource.setUsername("root");
dataSource.setPassword("root");

2.创建jdbcTemplate对象，设置数据源

JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

测试crud

1.add

public void add() {
    String sql = "insert into user(username,password,sex,address) values(?,?,?,?)";
    jdbcTemplate.update(sql, "令狐冲", "123", "男", "华山");
}

2.delete

String sql = "delete from user where userId = ?";
jdbcTemplate.update(sql, 2);

3.update

String sql = "update user set password = ? where userId = ?";
jdbcTemplate.update(sql, "lhc", 3);

4.select

4.1 查询有多少条数据：

public Integer selectNum() {
    String sql = "select count(*) from user";
    //第二个参数是返回类型
    Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
    return count;
}

4.2 查询返回对象

public User selectUser() {
    String sql = "select * from user where userId = ?";
    //需要自己写一个继承RowMapper接口的实现类
    User user  = (User) jdbcTemplate.queryForObject(sql, new MyRowMapper(), 3);
    return user;
}
class MyRowMapper implements RowMapper{
    @Override
    public User mapRow(ResultSet resultSet, int i) throws SQLException {
        //从结果集中拿到数据
        String userId = resultSet.getString("userId");
        String username = resultSet.getString("username");
        String password = resultSet.getString("password");
        String sex = resultSet.getString("sex");
        String address = resultSet.getString("address");
        //把得到的数据封装到对象中
        User user = new User();
        user.setUserId(Integer.valueOf(userId));
        user.setUsername(username);
        user.setPassword(password);
        user.setSex(sex);
        user.setAddress(address);
        return user;
    }
}

4.3 查询返回list

public List<User> selectUserList() {
    String sql = "select * from user";
    List<User> list = jdbcTemplate.query(sql, new MyRowMapper());
    return list;
}