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JDBC面向接口编程

时间：2021-07-01 10:21:17 帮助过：13人阅读

cn.code.dao; import cn.code.domain.User; public interface UserDao { public void add(User form); public User find(String username); }

//给出工厂类

  1. <span style="color: #0000ff">package</span><span style="color: #000000"> cn.code.dao;
  2. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.IOException;
  3. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.InputStream;
  4. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.util.Properties;
  5. </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">class</span><span style="color: #000000"> UserDaoFactory {
  6.     </span><span style="color: #0000ff">static</span> Properties props =<span style="color: #0000ff">null</span><span style="color: #000000">;
  7.     </span><span style="color: #0000ff">static</span> String impclassname =<span style="color: #0000ff">null</span><span style="color: #000000">;
  8.     </span><span style="color: #0000ff">static</span><span style="color: #000000">{
  9.         props </span>= <span style="color: #0000ff">new</span><span style="color: #000000"> Properties();
  10.         InputStream in </span>= UserDaoFactory.<span style="color: #0000ff">class</span>.getClassLoader().getResourceAsStream("UserDao.properties"<span style="color: #000000">);
  11.         </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  12.             props.load(in);
  13.         } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (IOException e) {
  14.             </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
  15. <span style="color: #000000">            e.printStackTrace();
  16.         }
  17.         impclassname </span>= props.getProperty("cn.code.dao.UserDao"<span style="color: #000000">);
  18.     }
  19.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span><span style="color: #000000"> UserDao getUserdaoimp(){
  20.             </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  21.                 Class clazz </span>=<span style="color: #000000"> Class.forName(impclassname);
  22.                 </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  23.                     </span><span style="color: #0000ff">return</span><span style="color: #000000"> (UserDao)clazz.newInstance();
  24.                 } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (InstantiationException e) {
  25.                     </span><span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span><span style="color: #000000"> RuntimeException(e);
  26.                 } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (IllegalAccessException e) {
  27.                     </span><span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span><span style="color: #000000"> RuntimeException(e);
  28.                 }
  29.             } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (ClassNotFoundException e) {
  30.                 </span><span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span><span style="color: #000000"> RuntimeException(e);
  31.             }
  32.     }
  33. }</span>

//工厂类配置文件

  1. cn.code.dao.UserDao=cn.code.dao.UserDaoImp

//实现类

  1. <span style="color: #0000ff">package</span><span style="color: #000000"> cn.code.dao;
  2. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.Connection;
  3. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.PreparedStatement;
  4. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.ResultSet;
  5. </span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.SQLException;
  6. </span><span style="color: #0000ff">import</span><span style="color: #000000"> cn.code.DBUtils1.DBUtils1;
  7. </span><span style="color: #0000ff">import</span><span style="color: #000000"> cn.code.domain.User;
  8. </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">class</span> UserDaoImp <span style="color: #0000ff">implements</span><span style="color: #000000"> UserDao {
  9.     @Override
  10.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">void</span><span style="color: #000000"> add(User form) {
  11.         Connection con </span>=<span style="color: #000000"> DBUtils1.getConnection();
  12.         PreparedStatement ps </span>=<span style="color: #0000ff">null</span><span style="color: #000000">;
  13.         String sql </span>= "INSERT INTO user values(?,?)"<span style="color: #000000">;
  14.         </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  15.              ps </span>=<span style="color: #000000"> con.prepareStatement(sql);
  16.             ps.setString(</span>1<span style="color: #000000">,form.getUsername());
  17.             ps.setString(</span>2<span style="color: #000000">,form.getPassword());
  18.             ps.executeUpdate();
  19.         } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (SQLException e) {
  20.             </span><span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span><span style="color: #000000"> RuntimeException();
  21.         }</span><span style="color: #0000ff">finally</span><span style="color: #000000">{
  22.             </span><span style="color: #0000ff">if</span>(ps!=<span style="color: #0000ff">null</span><span style="color: #000000">)
  23.                 </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  24.                     ps.close();
  25.                 } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (SQLException e) {
  26.                     </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
  27. <span style="color: #000000">                    e.printStackTrace();
  28.                 }
  29.             </span><span style="color: #0000ff">if</span>(con!=<span style="color: #0000ff">null</span><span style="color: #000000">)
  30.                 </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  31.                     con.close();
  32.                 } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (SQLException e) {
  33.                     </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
  34. <span style="color: #000000">                    e.printStackTrace();
  35.                 }
  36.         }
  37.     }
  38.     @Override
  39.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> User find(String username) {
  40.         Connection con </span>=<span style="color: #000000"> DBUtils1.getConnection();
  41.         String sql </span>= "select * from user where username=?"<span style="color: #000000">;
  42.         </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
  43.             PreparedStatement ps </span>=<span style="color: #000000"> con.prepareStatement(sql);
  44.             ps.setString(</span>1<span style="color: #000000">,username);
  45.             ResultSet rs </span>=<span style="color: #000000"> ps.executeQuery();
  46.             </span><span style="color: #0000ff">if</span>(rs==<span style="color: #0000ff">null</span><span style="color: #000000">){
  47.                 </span><span style="color: #0000ff">return</span> <span style="color: #0000ff">null</span><span style="color: #000000">;
  48.             }
  49.             </span><span style="color: #0000ff">if</span><span style="color: #000000">(rs.next()){
  50.                 User user </span>= <span style="color: #0000ff">new</span><span style="color: #000000"> User();
  51.                 user.setUsername(rs.getString(</span>"username"<span style="color: #000000">));
  52.                 user.setPassword(rs.getString(</span>"password"<span style="color: #000000">));
  53.                 </span><span style="color: #0000ff">return</span><span style="color: #000000"> user;
  54.             }</span><span style="color: #0000ff">else</span><span style="color: #000000">{
  55.                 </span><span style="color: #0000ff">return</span> <span style="color: #0000ff">null</span><span style="color: #000000">;
  56.             }
  57.         } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (SQLException e) {
  58.             </span><span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span><span style="color: #000000"> RuntimeException(e);
  59.         }
  60.         
  61.     }
  62.     
  63. }</span>

//service层

  1. <span style="color: #0000ff">package</span><span style="color: #000000"> cn.code.service;
  2. </span><span style="color: #0000ff">import</span><span style="color: #000000"> cn.code.dao.UserDao;
  3. </span><span style="color: #0000ff">import</span><span style="color: #000000"> cn.code.dao.UserDaoFactory;
  4. </span><span style="color: #0000ff">import</span><span style="color: #000000"> cn.code.domain.User;
  5. </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">class</span><span style="color: #000000"> UserService {
  6.     </span><span style="color: #0000ff">private</span> UserDao userDaoImp =<span style="color: #000000"> UserDaoFactory.getUserdaoimp();
  7.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">void</span> regist(User user)<span style="color: #0000ff">throws</span><span style="color: #000000"> UserException{
  8.         </span><span style="color: #008000">/**</span><span style="color: #008000">
  9.          * 使用用户名去查询，如果返回null，完成添加
  10.          * 如果返回布市null，抛出异常！
  11.          * </span><span style="color: #008000">*/</span><span style="color: #000000">
  12.         User u </span>=<span style="color: #000000"> userDaoImp.find(user.getUsername());
  13.         </span><span style="color: #0000ff">if</span>(u!=<span style="color: #0000ff">null</span>)<span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span> UserException("用户名"+user.getUsername()+"已经被注册！"<span style="color: #000000">);
  14.         userDaoImp.add(user);
  15.         
  16.     }
  17.     </span><span style="color: #0000ff">public</span> User login(User user) <span style="color: #0000ff">throws</span><span style="color: #000000"> UserException {
  18.         User u </span>=<span style="color: #000000"> userDaoImp.find(user.getUsername());
  19.         </span><span style="color: #0000ff">if</span>(u==<span style="color: #0000ff">null</span>)<span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span> UserException("用户名不存在！"<span style="color: #000000">);
  20.         </span><span style="color: #0000ff">if</span>(!<span style="color: #000000">u.getPassword().equals(user.getPassword())){
  21.             </span><span style="color: #0000ff">throw</span> <span style="color: #0000ff">new</span> UserException("密码错误"<span style="color: #000000">);
  22.         }
  23.         </span><span style="color: #0000ff">return</span><span style="color: #000000"> u;
  24.     }
  25. }</span>

//domain层

  1. <span style="color: #0000ff">package</span><span style="color: #000000"> cn.code.domain;
  2. </span><span style="color: #008000">/*</span><span style="color: #008000">
  3.  * 实体类
  4.  * </span><span style="color: #008000">*/</span>
  5. <span style="color: #0000ff">public</span> <span style="color: #0000ff">class</span><span style="color: #000000"> User {
  6.     </span><span style="color: #0000ff">private</span><span style="color: #000000"> String username;
  7.     </span><span style="color: #0000ff">private</span><span style="color: #000000"> String password;
  8.     </span><span style="color: #0000ff">private</span><span style="color: #000000"> String verifyCode;
  9.     
  10.     @Override
  11.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> String toString() {
  12.         </span><span style="color: #0000ff">return</span> "User [username=" + username + ", password=" +<span style="color: #000000"> password
  13.                 </span>+ ", verifyCode=" + verifyCode + "]"<span style="color: #000000">;
  14.     }
  15.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> User(String username, String password, String verifyCode) {
  16.         </span><span style="color: #0000ff">super</span><span style="color: #000000">();
  17.         </span><span style="color: #0000ff">this</span>.username =<span style="color: #000000"> username;
  18.         </span><span style="color: #0000ff">this</span>.password =<span style="color: #000000"> password;
  19.         </span><span style="color: #0000ff">this</span>.verifyCode =<span style="color: #000000"> verifyCode;
  20.     }
  21.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> String getUsername() {
  22.         </span><span style="color: #0000ff">return</span><span style="color: #000000"> username;
  23.     }
  24.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">void</span><span style="color: #000000"> setUsername(String username) {
  25.         </span><span style="color: #0000ff">this</span>.username =<span style="color: #000000"> username;
  26.     }
  27.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> String getPassword() {
  28.         </span><span style="color: #0000ff">return</span><span style="color: #000000"> password;
  29.     }
  30.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">void</span><span style="color: #000000"> setPassword(String password) {
  31.         </span><span style="color: #0000ff">this</span>.password =<span style="color: #000000"> password;
  32.     }
  33.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> String getVerifyCode() {
  34.         </span><span style="color: #0000ff">return</span><span style="color: #000000"> verifyCode;
  35.     }
  36.     </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">void</span><span style="color: #000000"> setVerifyCode(String verifyCode) {
  37.         </span><span style="color: #0000ff">this</span>.verifyCode =<span style="color: #000000"> verifyCode;
  38.     }
  39.     </span><span style="color: #0000ff">public</span><span style="color: #000000"> User() {
  40.     }
  41.     
  42. }</span>

 

JDBC面向接口编程

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