Spring全解-04-資料處理及跳轉
阿新 • • 發佈:2021-06-25
結果跳轉方式
ModelAndView
設定ModelAndView物件,根據view的名稱,和檢視解析器跳到指定的頁面。
頁面:檢視解析器字首+ViewName+檢視解析器字尾
<!-- 檢視解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver"> <!-- 字首 --> <property name="prefix" value="/WEB-INF/jsp/"/> <!-- 字尾 --> <property name="suffix" value=".jsp" /> </bean>
public class ControllerTest1 implements Controller { public ModelAndView handleRequest(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) throws Exception { //返回一個模型檢視物件 ModelAndView mv = newModelAndView(); mv.addObject("msg","ControllerTest1"); mv.setViewName("test"); return mv; } }
@Controller public class ResultGo { @RequestMapping("/result/t1") public void test1(HttpServletRequest req, HttpServletResponse rsp) throwsIOException { rsp.getWriter().println("Hello,Spring BY servlet API"); } @RequestMapping("/result/t2") public void test2(HttpServletRequest req, HttpServletResponse rsp) throwsIOException { rsp.sendRedirect("/index.jsp"); } @RequestMapping("/result/t3") public void test3(HttpServletRequest req, HttpServletResponse rsp) throwsException { //轉發 req.setAttribute("msg","/result/t3"); req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,rsp); } }
@Controller public class ResultSpringMVC { @RequestMapping("/rsm/t1") public String test1(){ //轉發 return "/index.jsp"; } @RequestMapping("/rsm/t2") public String test2(){ //轉發二 return "forward:/index.jsp"; } @RequestMapping("/rsm/t3") public String test3(){ //重定向 return "redirect:/index.jsp"; } }
資料處理
處理提交資料
1.當提交的域名稱和處理方法的引數名一致。
提交資料:http://localhost:8080/hello?name=fuyao
處理方法
@RequestMapping("/hello") public String hello(String name){ System.out.println(name); return "hello"; }
2.當提交的域名稱和處理方法的引數名不一致。 關鍵字:@RequestParam
提交資料:http://localhost:8080/hello?username=fuyao
處理方法
//@RequestParam("username") : username提交的域的名稱 . @RequestMapping("/hello") public String hello(@RequestParam("username") String name){ System.out.println(name); return "hello"; }
3.當提交的是一個物件
public class User { private int id; private String name; private int age; //構造 //get/set //tostring() }
提交資料:http://localhost:8080/hello/user?name=fuyao&id=1&age=20
處理方法
@RequestMapping("/user") public String user(User user){ System.out.println(user); return "hello"; }
如果使用物件的話,前端傳遞的引數名和物件名必須一致,否則就是null。
資料顯示到前端
第一種實現方式:通過ModelAndView
public class ControllerTest1 implements Controller { public ModelAndView handleRequest(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) throws Exception { //返回一個模型檢視物件 ModelAndView mv = new ModelAndView(); mv.addObject("msg","ControllerTest1"); mv.setViewName("test"); return mv; } }
第二種實現方式:通過ModelMap
@RequestMapping("/hello") public String hello(@RequestParam("username") String name, ModelMap model){ //封裝要顯示到檢視中的資料 //相當於req.setAttribute("name",name); model.addAttribute("name",name); System.out.println(name); return "hello"; }
第三種實現方式:通過Model
@RequestMapping("/ct2/hello") public String hello(@RequestParam("username") String name, Model model){ //封裝要顯示到檢視中的資料 //相當於req.setAttribute("name",name); model.addAttribute("msg",name); System.out.println(name); return "test"; }
後端向前端傳遞資料的亂碼問題解決
在之前,我們處理亂碼是自定義一個過濾器,現在,SpringMVC提供了一個內部的過濾器,直接在web.xml中配置即可。
<filter> <filter-name>encoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>utf-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>encoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
有些極端情況下,這個過濾器對get方法不友好。
你也可以在tomcat配置檔案 :設定編碼
<Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />
如果都解決不了,就使用自定義的過濾器
package com.li.filter; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.util.Map; /** * 解決get和post請求 全部亂碼的過濾器 */ public class GenericEncodingFilter implements Filter { @Override public void destroy() { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChainchain) throws IOException, ServletException { //處理response的字元編碼 HttpServletResponse myResponse=(HttpServletResponse) response; myResponse.setContentType("text/html;charset=UTF-8"); // 轉型為與協議相關物件 HttpServletRequest httpServletRequest = (HttpServletRequest) request; // 對request包裝增強 HttpServletRequest myrequest = new MyRequest(httpServletRequest); chain.doFilter(myrequest, response); } @Override public void init(FilterConfig filterConfig) throws ServletException { } } //自定義request物件,HttpServletRequest的包裝類 class MyRequest extends HttpServletRequestWrapper { private HttpServletRequest request; //是否編碼的標記 private boolean hasEncode; //定義一個可以傳入HttpServletRequest物件的建構函式,以便對其進行裝飾 public MyRequest(HttpServletRequest request) { super(request);// super必須寫 this.request = request; } // 對需要增強方法 進行覆蓋 @Override public Map getParameterMap() { // 先獲得請求方式 String method = request.getMethod(); if (method.equalsIgnoreCase("post")) { // post請求 try { // 處理post亂碼 request.setCharacterEncoding("utf-8"); return request.getParameterMap(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } else if (method.equalsIgnoreCase("get")) { // get請求 Map<String, String[]> parameterMap = request.getParameterMap(); if (!hasEncode) { // 確保get手動編碼邏輯只執行一次 for (String parameterName : parameterMap.keySet()) { String[] values = parameterMap.get(parameterName); if (values != null) { for (int i = 0; i < values.length; i++) { try { // 處理get亂碼 values[i] = new String(values[i] .getBytes("ISO-8859-1"), "utf-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } } } hasEncode = true; } return parameterMap; } return super.getParameterMap(); } //取一個值 @Override public String getParameter(String name) { Map<String, String[]> parameterMap = getParameterMap(); String[] values = parameterMap.get(name); if (values == null) { return null; } return values[0]; // 取回引數的第一個值 } //取所有值 @Override public String[] getParameterValues(String name) { Map<String, String[]> parameterMap = getParameterMap(); String[] values = parameterMap.get(name); return values; } }
然後在web.xml中配置這個過濾器即可。