Spring中的jdbcTemplate操作

準備工作

1.設定資料庫資訊

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

2.建立jdbcTemplate物件，設定資料來源

JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

測試crud

1.add

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

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 查詢有多少條資料：

public Integer selectNum() {
    String sql = "select count(*) from user";
    //第二個引數是返回型別
    Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
    return
 
 count;
}

4.2 查詢返回物件

public User selectUser() {
    String sql = "select * from user where userId = ?";
    //需要自己寫一個繼承RowMapper介面的實現類
    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 {
        //從結果集中拿到資料
        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");
        //把得到的資料封裝到物件中
        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 查詢返回list

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