201912G05/src\\BA_Control/pieChange.java

package BA_Control;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
//import java.sql.ResultSet;
//import java.sql.Statement;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class pieChange extends HttpServlet {
	public static final String DBURL = "jdbc:mysql://localhost:3306/kui?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=UTF-8";
	public static final String DBUSER = "root";
	public static final String DBPASS = "001011";
	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;UTF-8");
		// 输出流
		PrintWriter out = response.getWriter();
		// 数据库连接代码
		try {
			
			//修改
			String changeName = request.getParameter("changeName");
			String changeScore = request.getParameter("changeScore");
			
			Connection conn = null; // 表示数据库的连接的对象
			//Statement stmt = null; // 表示数据库的更新操作 
			PreparedStatement ps = null;

			// 1、使用Class类加载驱动程序
			try {
				Class.forName("com.mysql.jdbc.Driver");
			} catch (ClassNotFoundException e) {
				out.print("找不到driver");
				e.printStackTrace();
			}

			// 2、连接数据库
			conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
			//stmt = conn.createStatement();

			//修改
			if(!changeName.equals("") && !changeScore.equals("")) {
				out.println("进来修改啦");
				try {
					ps = conn.prepareStatement("update pie set score =" + changeScore + " where name =\"" + changeName + "\""); //转义字符串\,因为changeName是字符串,注意这里不要手贱加了空格
					ps.executeUpdate();
				} catch (Exception e) {
					out.print("修改出了点问题");
					e.printStackTrace();
				}
			}
			
			
			conn.close();

		} catch (Exception e) {
			e.printStackTrace();
		}
			out.flush();
			out.close();

	}

}