JDBC连接Mysql(连接、增删查改)

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import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement;  public class DBHelper {    public static String classname = "com.mysql.jdbc.Driver";    public static String url = "jdbc:mysql://localhost:3306/test";    public static String username = "root";    public static String password = "123456789";    public static Connection con;    public static Statement stmt;    public static ResultSet rs;    public static PreparedStatement pstmt;         public static void connect() {                // 建立连接        try{Class.forName(classname );System.out.println("加载驱动成功!");            con = DriverManager.getConnection(url, username, password);            stmt = con.createStatement();            System.out.println("数据库连接成功!");         }catch(SQLException e){            System.out.println("数据库连接失败!");            e.printStackTrace();        }catch (ClassNotFoundException e){            System.out.println("加载驱动失败!");            e.printStackTrace();        }    }    public static ResultSet select(String sql) {        try{            //传入类似sql="select * from test"            pstmt=con.prepareStatement(sql); //只有查询用executeQuery 其他增删改都用executeUpdate            rs=pstmt.executeQuery();            while (rs.next()) {             System.out.println("xxx为数据库字段名："+rs.getString("XXX"));              System.out.println("获取第一个字段："+rs.getInt(0));             }            rs.close();        }catch (Exception e){            System.out.println("数据查询失败!");            e.printStackTrace();        }return rs;    }/*其他地方用的时候DBHelper dbHelper = new DBHelper();dbHelper.connect();String sql = "select * from test";ResultSet resultset = dbHelper.select(sql);while(resultset.next()){String XX = resultset.getString("XXX");或者int xx = resultset.getInt("xxx");}dbHelper.close();*/    public static void insert(String sql) {        try{            //sql="insert into test (id,name) values('123','xxx')"            stmt.executeUpdate(sql);            System.out.println("数据插入成功!");        }catch (Exception e) {            System.out.println("数据插入失败!");            e.printStackTrace();        }             }    public static void update(String sql) {        try{            //sql="update test set name='rootroot' where id=1";            stmt.executeUpdate(sql);            System.out.println("数据更新成功!");        }catch (Exception e) {            System.out.println("数据更新失败!");            e.printStackTrace();        }    }    public static void delete(String sql) {        try{            //sql="delete from test where id=123"            pstmt = con.prepareStatement(sql);            pstmt.executeUpdate();            System.out.println("数据删除成功!");        }catch(Exception e){            System.out.println("数据删除失败!");            e.printStackTrace();        }    }//关闭数据库连接    public static void close() {     try{      if(rs!=null)             rs.close();      if(stmt!=null)             stmt.close();      if(con!=null)             con.close();     }catch(Exception e)     {      e.printStackTrace();     }    }     }
附件：
http://download.csdn.net/detail/qq_22778717/9630639
写之前导入个mysql-connector-java.jar
基本上就这样了
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