javajdbc(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);
		}	
	}
}