1、返回ModelAndView

ModelAndView中的视图会经过你视图解析器处理得到真实的jsp文件页面并且跳转。

@RequestMapping("test01")public ModelAndView test01() {ModelAndView mv = new ModelAndView();// 携带数据mv.addObject("teamName", "牛逼");// 页码转载mv.setViewName("result");// 经过视图解析器处理： /jsp/result.jspreturn mv;}

2、返回字符串

默认还是会经过视图解析器，将该字符串转为对应的jsp页面地址以及跳转

@RequestMapping("test02")public String test02(HttpServletRequest req) {Team team = new Team();team.setLocation("henan");team.setTeamId(12);team.setTeamName("AE");// 携带数据req.setAttribute("team", team);req.getSession().setAttribute("team", team);// 页面跳转return "result";}

3、返回对象类型

任意对象类型都可以返回，而是直接作为数据返回后直接展示，一般都是前端发起ajax异步请求
返回的时候需要添加注解@ResponseBody ，将对象转化为你json格式的数据放入到响应体，所以需要引入json依赖

前端可以通过ajax进行请求，然后对返回值进行获取

加上@ResponseBody注解之后，返回值不会经过视图解析器，所以返回值只是单纯的字符串，不会进行页面的跳转。

<dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId><version>2.9.0</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.9.0</version></dependency>

    @ResponseBody@RequestMapping("test03-1")public Integer test031(HttpServletRequest req) {return 66;}@ResponseBody@RequestMapping("test03-2")public String test032(HttpServletRequest req) {return "test"; // 直接返回数据，分返回字符串区别开}@ResponseBody@RequestMapping("test03-3")public Team test033(HttpServletRequest req) {Team team = new Team();team.setLocation("南阳");team.setTeamId(12);team.setTeamName("AE");return team;}@ResponseBody@RequestMapping("test03-4")public List<Team> test034(HttpServletRequest req) {List<Team> teams = new ArrayList<Team>();for(int i = 1;  i < 5; i ++){Team team = new Team();team.setLocation("南阳" + i);team.setTeamId(12+i);team.setTeamName("AE"+i);teams.add(team);}return teams;}@ResponseBody@RequestMapping("test03-5")public Map<String, Team> test035(HttpServletRequest req) {Map<String, Team> teams = new HashMap<String, Team>();for(int i = 1;  i < 5; i ++){Team team = new Team();team.setLocation("南阳" + i);team.setTeamId(12+i);team.setTeamName("AE"+i);team.setDate(new Date());teams.put(team.getTeamId()+"", team);}return teams;}

4、无返回值

    //通过 HttpServletRequest 做服务端跳转@RequestMapping("test04-1")public void test041(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {System.out.println("直接使用HttpServletRequest进行服务器转发");req.getRequestDispatcher("/jsp/OK.jsp").forward(req, resp);}//通过 HttpServletResponse 做重定向@RequestMapping("test04-2")public void test042(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {System.out.println("直接使用HttpServletResponse进行客户端重定向");resp.sendRedirect("/jsp/OK.jsp");}//通过 HttpServletResponse 给出响应@RequestMapping("test04-3")public void test043(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {resp.setCharacterEncoding("UTF-8");resp.setContentType("text/html:charset=utf-8");System.out.println("返回void类型测试---直接返回字符串");PrintWriter writer = resp.getWriter();writer.write("返回void类型测试---直接返回字符串");writer.flush();writer.close();}//也可以自己手动指定响应头去实现重定向：@RequestMapping("test04-4")public void test044(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {resp.setStatus(302);resp.setHeader("Location", "/jsp/OK.jsp");}