java----jdbc，数据库的添加，删除，修改，更新

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class Mtest4Demo {
/*
 * jdbc工具类
 * 提供获取连接和释放资源的方法
 */
        public static Connection getConnection() throws ClassNotFoundException {
                Connection conn=null;
                try {
                  Class.forName("com.mysql.jdbc.Driver");
                  conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/study","root","root");
                } catch (Exception e) {
                        // TODO: handle exception
                        e.printStackTrace();
                }
                
                return conn;
        }
        public static void release(Connection conn,PreparedStatement pstmt,ResultSet rSet) {
                if(rSet!=null)
                {
                        try {
                                rSet.close();
                        } catch (Exception e) {
                                e.printStackTrace();
                        }
                }
                if(conn!=null)
                {
                        try {
                                conn.close();
                        } catch (Exception e) {
                                // TODO: handle exception
                                e.printStackTrace();
                        }
                }
                if(pstmt!=null)
                {
                        try {
                                pstmt.close();
                        } catch (Exception e) {
                                // TODO: handle exception
                                e.printStackTrace();
                        }
                }
         }
        //添加信息
        public int testAdd(String sqlString) {
                Connection conn=null;
                PreparedStatement pstmt=null;
                Mtest4Demo mtest4Demo=new Mtest4Demo();
                try {
                        conn=mtest4Demo.getConnection();
                        pstmt=conn.prepareStatement(sqlString);
                        int row=pstmt.executeUpdate();
                        if(row>0)
                        {
                                return 1;
                        }else {
                                return 0;
                        }
                        
                } catch (Exception e) {
                        // TODO: handle exception
                        e.printStackTrace();
                }
                return 0;
        }
        public int testDeleteByName(String username) {
                Connection conn=null;
                PreparedStatement pstmt=null;
                Mtest4Demo mtest4Demo=new Mtest4Demo();
                try {
                        conn=mtest4Demo.getConnection();
                        String sqlString="delete from login where "+"username='"+username+"'";
                        pstmt=conn.prepareStatement(sqlString);
                        int row=pstmt.executeUpdate();
                        if(row>0)
                        {
                                return 1;
                        }else {
                                return 0;
                        }
                        
                } catch (Exception e) {
                        // TODO: handle exception
                        e.printStackTrace();
                }
                return 0;
        }
        //根据姓名修改相关的信息
        public int UpdateByName(String name,String username,String password) {
                Connection conn=null;
                PreparedStatement pstmt=null;
                Mtest4Demo mtest4Demo=new Mtest4Demo();
                try {
                        conn=mtest4Demo.getConnection();
                        String sqlString="update login set username=?,password=? where username=?";
                        pstmt=conn.prepareStatement(sqlString);
                        pstmt.setString(1, username);
                        pstmt.setString(2, password);
                        pstmt.setString(3, name);
                        int row=pstmt.executeUpdate();
                        if(row>0)
                        {
                                return 1;
                        }else {
                                return 0;
                        }
                        
                } catch (Exception e) {
                        // TODO: handle exception
                        e.printStackTrace();
                }
                return 0;
        }
}

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

public class Mtest5Demo {
        public static void main(String[] args) throws ClassNotFoundException, SQLException {
                Mtest4Demo mtest4Demo=new Mtest4Demo();
                Connection conn=null;
                PreparedStatement pstmt=null;
                ResultSet rSet=null;
                try {
                        conn=mtest4Demo.getConnection();
                        String sqlString="select *from login";
                        pstmt=conn.prepareStatement(sqlString);
                        rSet=pstmt.executeQuery();
                        while(rSet.next())
                        {
                                System.out.println(rSet.getString("username")+"---"+rSet.getString("password"));
                        }
                        String sqlString2="insert into login values ('test','test')";
                        int row=mtest4Demo.testAdd(sqlString2);
                        if(row==1)
                                System.out.println("信息添加成功");
                        else {
                                System.out.println("信息添加失败");
                        }
                        String nameString="zyz";
                        int delete=mtest4Demo.testDeleteByName(nameString);
                        if(delete==1) {
                                System.out.println("删除成功");
                        }else {
                                System.out.println("删除失败");
                        }
                        String name="test";
                        String username="1234567890";
                        String password="1234567890";
                        int update=mtest4Demo.UpdateByName(name, username, password);
                        if(update==1) {
                                System.out.println("信息修改成功");
                        }else {
                                System.out.println("数据修改失败");
                        }
                } catch (Exception e) {
                        // TODO: handle exception
                        e.printStackTrace();
                }finally {
                        mtest4Demo.release(conn, pstmt, rSet);
                }       
        }
}