基于JavaScript的餐厅点菜系统设计源码

package com.Web.Servlet.Persuit; import com.Bean.Test; import com.google.gson.Gson; import com.Model.JsonModel; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.Map; public abstract class CommonServlet extends HttpServlet { @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // request.setCharacterEncoding("utf-8"); //将功能转移到 CharacterFilter中完成 // Enumeration<String> headNames = request.getHeaderNames(); // String headName = ""; // while (headNames.hasMoreElements()) { // headName = headNames.nextElement(); // // if (headName.equals("User-Agent")) { // String value = request.getHeader(headName); // System.out.println("客户端系统类型：" + value); // } // } // String ip = request.getRemoteAddr(); // System.out.println(ip); // if (req.getHeader("referer") == null | "".equals(req.getHeader("referer"))) { // resp.setContentType("text/html;charset=utf-8"); // PrintWriter pw = resp.getWriter(); // pw.println("此请求为非法请求"); // pw.flush(); // return; // } super.service(request, response); } protected void writeJson(JsonModel jm, HttpServletResponse response) throws IOException { response.setContentType("application/json;charset=utf-8"); PrintWriter pw = response.getWriter(); Gson gson = new Gson(); String StringJson = gson.toJson(jm); pw.println(StringJson); pw.flush(); } protected void writeJson(Test jm, HttpServletResponse response) throws IOException { response.setContentType("application/json;charset=utf-8"); PrintWriter pw = response.getWriter(); Gson gson = new Gson(); String StringJson = gson.toJson(jm); pw.println(StringJson); pw.flush(); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String op = request.getParameter("op"); Method[] mm = this.getClass().getDeclaredMethods(); Method m = null; try { m = this.getClass().getDeclaredMethod(op,HttpServletRequest.class,HttpServletResponse.class); if (m == null) { out404("资源地址：" + op, response); } else { m.invoke(this, request, response); } } catch (Exception e) { e.printStackTrace(); out500(e.getMessage(), response); } } protected void out500(String message, HttpServletResponse response) throws IOException { response.setContentType("text/html;charset=utf-8"); PrintWriter pw = response.getWriter(); pw.println("服务器内部错误 500:<b>"); pw.println(message); pw.println("</b>"); pw.flush(); } protected void out404(String message, HttpServletResponse response) throws IOException { response.setContentType("text/html;charset=utf-8"); PrintWriter pw = response.getWriter(); pw.println("查无此资源，错误编码404:<b>"); pw.println(message); pw.println("</b>"); pw.flush(); } //protected 这个功能它的子类可以直接用，其他类不能用 /** * 将一个 Request转为 T 对象 */ protected <T> T parseRequestToT(HttpServletRequest request, Class<T> cls) throws IllegalAccessException, InstantiationException, InvocationTargetException { //1.通过class字节码创建一个对象 T T obj = cls.newInstance(); //2.从request中取出所有的属性，存到这个 obj中 Map<String, String[]> map = request.getParameterMap(); //3.取出cls中所有的属性，看有几个与map中的键相同，相同，则调用cls中的set方法，注入值 Method[] ms = cls.getMethods(); for (Method m : ms) { if (m.getName().startsWith("set")) { //这个m是一个setXXX()，取出XXX是什么，根据XXX，在map.get(XXX)取出这个值 String fieldName = getFieldName(m); String[] values = map.get(fieldName); String v = null; if (values != null) { if (values.length > 1) { StringBuffer sb = new StringBuffer(); for (String s : values) { sb.append(s + ","); } v = sb.toString(); } else { v = values[0]; } } if (v == null) { continue; } //判断这个 m方法的参数的类型，然后将 V 进行类型转换··· String methodParameterTypeName = m.getParameterTypes()[0].getTypeName(); if ("java.lang.Integer".equals(methodParameterTypeName)) { Integer va = Integer.parseInt(v); //然后再调用setXXX(),将值注入 m.invoke(obj, va); } else if ("java.lang.Double".equals(methodParameterTypeName)) { Double va = Double.parseDouble(v); //然后再调用setXXX(),将值注入 m.invoke(obj, va); } else if ("java.lang.Float".equals(methodParameterTypeName)) { Float va = Float.parseFloat(v); //然后再调用setXXX(),将值注入 m.invoke(obj, va); } else if ("java.lang.Long".equals(methodParameterTypeName)) { Long va = Long.parseLong(v); //然后再调用setXXX(),将值注入 m.invoke(obj, va); } else { m.invoke(obj, v); } } } return obj; } private String getFieldName(Method setMethod) { String fieldName = setMethod.getName().substring("set".length()); //将这个fieldNamed首字母改小写 fieldName = fieldName.substring(0, 1).toLowerCase() + fieldName.substring(1); return fieldName; } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } }