• 2020.11.19收获


    User.java
     
    package com.jaovo.msg.model;
    public class User {
     
     private int id;
     private String  name;
     private String  time;
     private String  jieci;
     private String  college;
     private String  tid;
     private String  tname;
     private String  number;
     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 String getTime()
     {
      return time;
     }
     public void setTime(String time)
     {
      this.time = time;
     }
     public String getJieci()
     {
      return jieci;
     }
     public void setJieci(String jieci)
     {
      this.jieci = jieci;
     }
     public String getCollege()
     {
      return college;
     }
     public void setCollege(String college)
     {
      this.college = college;
     }
     public String getTid()
     {
      return tid;
     }
     public void setTid(String tid)
     {
      this.tid = tid;
     }
     public String getTname()
     {
      return tname;
     }
     public void setTname(String tname)
     {
      this.tname = tname;
     }
     public String getNumber()
     {
      return number;
     }
     public void setNumber(String number)
     {
      this.number = number;
     }
     
    }
     
    CharFilter.java
    package com.jaovo.msg.filter;
    import java.io.IOException;
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    public class CharFilter implements Filter{
     String encoding = null;
     @Override
     public void init(FilterConfig filterConfig) throws ServletException{
      encoding = filterConfig.getInitParameter("encoding");
     }
     
     @Override
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
       throws IOException, ServletException {
    //   request.setCharacterEncoding("utf-8");
       request.setCharacterEncoding(encoding);
       chain.doFilter(request, response);
     }
     public void destroy() {
      // TODO Auto-generated method stub
      System.out.println();
     }
    }
     
    IUserDao.java
     
    package com.jaovo.msg.dao;
    import java.util.List;
    import com.jaovo.msg.model.User;
    public interface IUserDao {
     public void add(User user);
     public void delete(int id);
     public void update(User user);
     public User load(int id);
     public User load(String name);
     public List<User> load();
     
    }
     
    UserDaoImpl.java
     
    package com.jaovo.msg.dao;
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.ArrayList;
    import java.util.List;

    import com.jaovo.msg.Util.DBUtil;
    import com.jaovo.msg.Util.UserException;
    import com.jaovo.msg.model.User;
     
    public class UserDaoImpl implements IUserDao {
     //增
     public void add(User user) {
      //获得链接对象
      Connection connection = DBUtil.getConnection();
      //准备sql语句
      String sql = "select count(*) from class where name = ?";
     
      //创建语句传输对象
      PreparedStatement preparedStatement = null;
      ResultSet resultSet = null;
      try {
       preparedStatement = connection.prepareStatement(sql);
       preparedStatement.setString(1, user.getName());
       //接收结果集
       resultSet = preparedStatement.executeQuery();
       //遍历结果集
       while(resultSet.next()) {
        if (resultSet.getInt(1) > 0) {
         throw new UserException("用户已存在") ;
        }
       }
       
       sql = "insert into class(name,time,jieci,college,tid,tname,number) value (?,?,?,?,?,?,?)";
       preparedStatement = connection.prepareStatement(sql);
       //添加
       preparedStatement.setString(1, user.getName());
       preparedStatement.setString(2, user.getTime());
       preparedStatement.setString(3, user.getJieci());
       preparedStatement.setString(4, user.getCollege());
       preparedStatement.setString(5, user.getTid());
       preparedStatement.setString(6, user.getTname());
       preparedStatement.setString(7, user.getNumber());
       preparedStatement.executeUpdate();
      } catch (SQLException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }finally {
       //关闭资源
       DBUtil.close(resultSet);
       DBUtil.close(preparedStatement);
       DBUtil.close(connection);
      }
      
     }
     //删
     public void delete(int id) {
      //获得链接对象
      Connection connection = DBUtil.getConnection();
      String sql = "delete from class where id = ?";
      PreparedStatement preparedStatement = null;
      try {
       preparedStatement = connection.prepareStatement(sql);
       preparedStatement.setInt(1, id);
       preparedStatement.executeUpdate();
      } catch (SQLException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }finally {
       DBUtil.close(preparedStatement);
       DBUtil.close(connection);
      }
      
     }
     //改
     @Override
     public void update(User user) {
      //获得链接对象
      Connection connection = DBUtil.getConnection();
      //准备sql语句
      String sql = "update class set time = ? , jieci=? , college=? , tid=? , tname=? , number=? where id = ?";
      //创建语句传输对象
      PreparedStatement preparedStatement = null;
      try {
       preparedStatement = connection.prepareStatement(sql);
       preparedStatement.setString(1, user.getTime());
       preparedStatement.setString(2, user.getJieci());
       preparedStatement.setString(3, user.getCollege());
       preparedStatement.setString(4, user.getTid());
       preparedStatement.setString(5, user.getTname());
       preparedStatement.setString(6, user.getNumber());
       preparedStatement.setInt(7, user.getId());
       preparedStatement.executeUpdate();
      } catch (SQLException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }finally {
       DBUtil.close(preparedStatement);
       DBUtil.close(connection);
      }
     }
     @Override
     public User load(int id) {
      //获得链接对象
      Connection connection = DBUtil.getConnection();
      //准备sql语句
      String sql = "select * from class  where id = ?";
      //创建语句传输对象
      PreparedStatement preparedStatement = null;
      ResultSet resultSet = null;
      User user = null;
      try {
       preparedStatement = connection.prepareStatement(sql);
       preparedStatement.setInt(1, id);
       resultSet = preparedStatement.executeQuery();
       while(resultSet.next()) {
        user = new User();
        user.setId(id);
        user.setName(resultSet.getString("name"));
        user.setTime(resultSet.getString("time"));
        user.setJieci(resultSet.getString("jieci"));
        user.setCollege(resultSet.getString("college"));
        user.setTid(resultSet.getString("tid"));
        user.setTname(resultSet.getString("tname"));
        user.setNumber(resultSet.getString("number"));
       }
      } catch (SQLException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }finally {
       DBUtil.close(resultSet);
       DBUtil.close(preparedStatement);
       DBUtil.close(connection);
      }
      return  user;
     }
     @Override
     public User load(String name) {
      // TODO Auto-generated method stub
      return null;
     }
     @Override
     public List<User> load() {
      Connection connection = DBUtil.getConnection();
      //准备sql语句
      String sql = "select * from class ";
      //创建语句传输对象
      PreparedStatement preparedStatement = null;
      ResultSet resultSet = null;
      //集合中只能放入user对象
      List<User> users = new ArrayList<User>();
      User user = null;
      try {
       preparedStatement = connection.prepareStatement(sql);
       resultSet = preparedStatement.executeQuery();
       while(resultSet.next()) {
        user = new User();
        user.setId(resultSet.getInt("id"));
        user.setName(resultSet.getString("name"));
        user.setTime(resultSet.getString("time"));
        user.setJieci(resultSet.getString("jieci"));
        user.setCollege(resultSet.getString("college"));
        user.setTid(resultSet.getString("tid"));
        user.setTname(resultSet.getString("tname"));
        user.setNumber(resultSet.getString("number"));
        users.add(user);
       }
      } catch (SQLException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }finally {
       DBUtil.close(resultSet);
       DBUtil.close(preparedStatement);
       DBUtil.close(connection);
      }
      return  users;
     }
    }
     
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  • 原文地址:https://www.cnblogs.com/ltw222/p/14067696.html
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