完成整个DAO的实现及测试代码

 package cn.itcast.domain;

 import java.util.Date;

 public class User {

     private int id;
     private String name;
     private Date birthday;
     private float money;

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public Date getBirthday() {
         return birthday;
     }

     public void setBirthday(Date birthday) {
         this.birthday = birthday;
     }

     public float getMoney() {
         return money;
     }

     public void setMoney(float money) {
         this.money = money;
     }

 }

User

 package cn.itcast.dao;

 import java.sql.SQLException;

 import cn.itcast.domain.User;

 public interface UserDao {

     public void addUser(User user) throws SQLException;

     public User getUser(int userId);

     public void update(User user);

     public void delete(User user);

     public User findUser(String userName,String password);

 }

UserDao

 package cn.itcast.dao.impl;

 import java.sql.Connection;
 import java.sql.Date;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;

 import cn.itcast.dao.UserDao;
 import cn.itcast.domain.User;
 import cn.itcast.exception.DaoException;
 import cn.itcast.jdbc.jdbcUtils;

 public class UserDaoJdbcImpl implements UserDao {

     @Override
     public void addUser(User user) throws DaoException {

         Connection conn = null;
         PreparedStatement ps = null;
         ResultSet rs = null;

         try {
             // 建立连接
             conn = jdbcUtils.getConnection();

             String sql = "insert into user(name,birthday,money) values(?,?,?)";
             ps = conn.prepareStatement(sql);

             ps.setString(1, user.getName());
             ps.setDate(2, new java.sql.Date(user.getBirthday().getTime()));
             ps.setFloat(3, user.getMoney());

             ps.executeUpdate();

         } catch (SQLException e) {
             throw new DaoException(e.getMessage(), e);
         } finally {
             jdbcUtils.free(rs, ps, conn);
         }

     }

     @Override
     public User getUser(int userId) {
         Connection conn = null;
         PreparedStatement ps = null;
         ResultSet rs = null;
         User user = null;

         try {
             conn = jdbcUtils.getConnection();
             String sql = "select id,name,money,birthday from user where id = ?";
             ps = conn.prepareStatement(sql);
             ps.setInt(1, userId);
             rs = ps.executeQuery();

             while (rs.next()) {

                 user = mappingUser(rs);

             }

         } catch (SQLException e) {
             throw new DaoException(e.getMessage());
         } finally {
             jdbcUtils.free(rs, ps, conn);
         }

         return user;
     }

     public User mappingUser(ResultSet rs) throws SQLException {
         User user = new User();
         user.setId(rs.getInt("id"));
         user.setName(rs.getString("name"));
         user.setMoney(rs.getFloat("money"));
         user.setBirthday(rs.getDate("birthday"));
         return user;
     }

     @Override
     public void update(User user) {
         Connection conn = null;
         PreparedStatement ps = null;
         ResultSet rs = null;

         try {
             conn = jdbcUtils.getConnection();
             String sql = "update user set name = ?,money=? where id=?";
             ps = conn.prepareStatement(sql);
             ps.setString(1, user.getName());
             //ps.setDate(2, new java.sql.Date(user.getBirthday().getTime()));
             ps.setFloat(2, user.getMoney());
             ps.setInt(3, user.getId());

             ps.executeUpdate();

         } catch (SQLException e) {
             new DaoException(e.getMessage());
         } finally {
             jdbcUtils.free(rs, ps, conn);
         }

     }

     @Override
     public void delete(User user) {

         Connection conn = null;
         Statement st = null;
         ResultSet rs = null;

         try {
             conn = jdbcUtils.getConnection();
             st = conn.createStatement();
             String sql = "delete from user where id=" + user.getId();
             st.executeUpdate(sql);

         } catch (SQLException e) {
             throw new DaoException(e.getMessage());
         } finally {
             jdbcUtils.free(rs, st, conn);
         }

     }

     @Override
     public User findUser(String userName, String password) {

         Connection conn = null;
         PreparedStatement ps = null;
         ResultSet rs = null;
         User user = null;

         try {
             conn = jdbcUtils.getConnection();
             String sql = "select id,name,money,birthday from user where name = ?";
             ps = conn.prepareStatement(sql);
             ps.setString(1, userName);
             rs = ps.executeQuery();

             while (rs.next()) {
                 user = mappingUser(rs);
             }

         } catch (SQLException e) {
             throw new DaoException(e.getMessage());
         } finally {
             jdbcUtils.free(rs, ps, conn);
         }

         return user;
     }

 }

UserDaoJdbcImpl

 package cn.itcast.exception;

 public class DaoException extends RuntimeException {

     private static final long serialVersionUID = 1L;

     public DaoException() {
         super();
         // TODO Auto-generated constructor stub
     }

     public DaoException(String message, Throwable cause) {
         super(message, cause);
         // TODO Auto-generated constructor stub
     }

     public DaoException(String message) {
         super(message);
         // TODO Auto-generated constructor stub
     }

     public DaoException(Throwable cause) {
         super(cause);
         // TODO Auto-generated constructor stub
     }

 }

DaoException

 package cn.itcast.jdbc;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;

 public class jdbcUtils {

     private static String url = "jdbc:mysql://localhost:3306/jdbc";
     private static String user = "root";
     private static String password = "123";

     private jdbcUtils() {

     }

     static {
         try {
             Class.forName("com.mysql.jdbc.Driver");
         } catch (ClassNotFoundException e) {
             e.printStackTrace();
         }
     }

     public static Connection getConnection() throws SQLException {
         return DriverManager.getConnection(url, user, password);
     }

     public static void free(ResultSet rs, Statement st, Connection conn) {

         try {
             if (rs != null)
                 rs.close();
         } catch (SQLException e) {
             e.printStackTrace();
         } finally {

             try {
                 if (st != null)
                     st.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             } finally {

                 try {
                     if (conn != null)
                         conn.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }

         }

     }
 }

jdbcUtils

 package cn.itcast.dao;

 import java.sql.SQLException;
 import java.util.Date;

 import cn.itcast.dao.impl.UserDaoJdbcImpl;
 import cn.itcast.domain.User;

 public class UserTest {

     /**
      * @param args
      * @throws SQLException
      */
     public static void main(String[] args) throws SQLException {

         UserDao userDao = new UserDaoJdbcImpl();

         //User user = new User();
         //user.setBirthday(new Date());
         //user.setName("dao name1");
         //user.setMoney(1000.0f);

 //        userDao.addUser(user);
 //
 //        User u = userDao.findUser(user.getName(),null);
 //        System.out.println(u.getId());

         User u = userDao.getUser(1);

         u.setMoney(2000.0f);
         userDao.update(u);

         User u1 = userDao.getUser(1);
         userDao.delete(u1);

     }

 }

UserTest