Tomcat 404 error: The origin server did not find a current representation for the target resource or
添加映射即可解决，添加@webServlet与路径文件名
package com.cjky;import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** Servlet implementation class UpdateServlet*/
@WebServlet("/UpdateServlet_modify") //缺少此句话就会出现“Tomcat 404 error: The origin server did not find a current representation for the target resource or”
public class UpdateServlet_modify extends HttpServlet {private static final long serialVersionUID = 1L;protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// int id = Integer.valueOf(request.getParameter("id"));// int bookCount = Integer.valueOf(request.getParameter("bookCount")); String mc_name=request.getParameter("mc_name");String modify_content=request.getParameter("modify_content");try {// 加载数据库驱动，注册到驱动管理器Class.forName("com.mysql.jdbc.Driver");// 数据库连接字符串String url = "jdbc:mysql://localhost:3306/db_cjky_pm";// 数据库用户名String username = "sa";// 数据库密码String password = "123456";// 创建Connection连接Connection conn = DriverManager.getConnection(url,username,password);// 更新SQL语句String sql = "update tb_books set modify_content=? where mc_name=?";// 获取PreparedStatementPreparedStatement ps = conn.prepareStatement(sql);// 对SQL语句中的第一个参数赋值ps.setString(1, modify_content);// 对SQL语句中的第二个参数赋值ps.setString(2, mc_name);// 执行更新操作ps.executeUpdate();// 关闭PreparedStatementps.close();// 关闭Connectionconn.close();} catch (Exception e) {e.printStackTrace();} // 重定向到FindServletresponse.sendRedirect("data_query_servlet");}}