Servlet案例五

com.jikexueyuan.dao包下新建UserDao.javapackage com.jikexueyuan.dao;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import com.jikexueyuan.entity.User;public interface UserDao {  public void save(Connection conn,User user) throws SQLException;  public void update(Connection conn,Long id,User user) throws SQLException;  public void delete(Connection conn,User user) throws SQLException;  public ResultSet get(Connection conn,User user)throws SQLException;}com.jikexueyuan.dao.impl包下新建UserDaoImpl.javapackage com.jikexueyuan.dao.impl;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import com.jikexueyuan.dao.UserDao;import com.jikexueyuan.entity.User;public class UserDaoImpl implements UserDao {/** *保存用户信息 */@Overridepublic void save(Connection conn, User user) throws SQLException {PreparedStatement ps = conn.prepareCall("INSERT INTO tbl_user(name,password,email) VALUES(?,?,?)");//?为占位符ps.setString(1, user.getName());//索引是从1开始的ps.setString(2, user.getPassword());ps.setString(3, user.getEmail());ps.execute();}/***根据用户指定的ID更新用户信息*/@Overridepublic void update(Connection conn, Long id, User user) throws SQLException {String updateSql = "UPDATE tbl_user SET name = ?,password = ?, email = ? WHERE id = ?";PreparedStatement ps = conn.prepareStatement(updateSql);ps.setString(1, user.getName());//索引是从1开始的ps.setString(2, user.getPassword());ps.setString(3, user.getEmail());ps.setLong(4,id);ps.execute();}/***删除指定的用户信息*/@Overridepublic void delete(Connection conn, User user) throws SQLException {PreparedStatement ps = conn.prepareStatement("DELETE FROM tbl_user WHERE id = ?");ps.setLong(1,user.getId());ps.execute();}@Overridepublic ResultSet get(Connection conn, User user) throws SQLException {PreparedStatement ps = conn.prepareStatement("SELECT * FROM tbl_user WHERE name = ? AND password = ?");ps.setString(1, user.getName());//索引是从1开始的ps.setString(2, user.getPassword());return ps.executeQuery();}}com.jikexueyuan.service包下新建CheckUserService.javapackage com.jikexueyuan.service;import java.sql.Connection;import java.sql.ResultSet;import com.jikexueyuan.dao.UserDao;import com.jikexueyuan.dao.impl.UserDaoImpl;import com.jikexueyuan.entity.User;import com.jikexueyuan.util.ConnectionFactory;public class CheckUserService {private UserDao userDao = new UserDaoImpl();public boolean check(User user){Connection conn = null;try {conn = ConnectionFactory.getInstance().makeConnection();conn.setAutoCommit(false);ResultSet resultSet = userDao.get(conn, user);while(resultSet.next()){return true;}} catch (Exception e) {e.printStackTrace();try {conn.rollback();} catch (Exception e2) {e2.printStackTrace();}}finally {try {conn.close();} catch (Exception e3) {e3.printStackTrace();}}return false;}}