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;
}