74 lines
2.6 KiB
Java
74 lines
2.6 KiB
Java
package com.qf.controller;
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import com.qf.utils.Constants;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServlet;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import java.io.IOException;
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import java.lang.reflect.Method;
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public class BaseServlet extends HttpServlet {
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/**
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* 重写service方法，来处理反射的业务逻辑
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*/
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@Override
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protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
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req.setCharacterEncoding("utf-8");
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//1.获取请求参数（标识符）
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String methodStr =req.getParameter(Constants.TAG);
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//2.如果method没有获取到值 就跳转到首页 （标识符异常处理）
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if (methodStr==null&& methodStr.equals("")){
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methodStr= Constants.INDEX;
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}
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//3.反射调用对应的业务逻辑方法
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Class clazz=this.getClass();
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try {
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Method method=clazz.getMethod(methodStr, HttpServletRequest.class, HttpServletResponse.class);
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Object result= method.invoke(this,req,resp);
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//4.集中处理返回值响应
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if (result != null) {
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//转发 重定向 返回字符串
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String str=(String)result;
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if (str.startsWith(Constants.FORWARD)){
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//转发 截取
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String path= str.substring(str.indexOf(Constants.FLAG)+1);
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req.getRequestDispatcher(path).forward(req,resp);
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}else if (str.startsWith(Constants.REDIRECT)){
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//重定向
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String path=str.substring(str.indexOf(Constants.FLAG)+1);
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resp.sendRedirect(path);
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}else{
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//就是要返回一个字符串
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resp.getWriter().println(str);
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}
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}
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} catch (Exception e) {
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e.printStackTrace();
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//没有反射到方法
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}
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}
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// /user?method=""
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//返回到首页的方法
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/**
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* 当method标识符"没有值"或者是空字符串时，我们默认赋index 访问每个Controller的index方法！
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* 我们将方法提取到BaseServlet中即可!
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* 默认处理：跳转到程序的首页！
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* @param req
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* @param resp
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* @return
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* @throws
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* @throws ServletException
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*/
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public String index (HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
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return Constants.FORWARD+"/index.jsp";
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}
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}
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