SpringMVC的Controller层参数绑定以及返回值

当客户端通过get或post请求发送来的参数通过Controller中方法的参数接受，叫做参数绑定

Controller方法的返回值1：返回void类型

@RequestMapping("/test_void.action")
public void controller01(HttpServletRequest request,HttpServletResponse response) throws Exception{
	request.setCharacterEncoding("utf-8");
	String username = request.getParameter("username");//通过HttpServletRequest获得请求参数
	System.out.println("用户名:"+username);
	request.setAttribute("username",username);
	User u = new User();
	u.setUsername(username);
	userService.insertUser(u);//插入数据库
	request.getRequestDispatcher("/WEB-INF/jsp/success.jsp").forward(request, response);//转发
}

@RequestMapping("/test_modelandview.action")
public ModelAndView controller02(HttpServletRequest request) throws Exception{
	request.setCharacterEncoding("utf-8");//转码，Tomcat默认是iso-8859-1
	String username = request.getParameter("username");
	System.out.println("用户名:"+username);
	ModelAndView modelAndView = new ModelAndView();	//new一个ModelAndView
	modelAndView.addObject("username",username);	//相当于request.setAttribute(attrName,attrValue);
	modelAndView.setViewName("WEB-INF/jsp/success.jsp");//视图跳转
	return modelAndView;
}

@RequestMapping("/test_string.action")
public String controller03(HttpServletRequest request) throws Exception{
	request.setCharacterEncoding("utf-8");	//转码
	String username = request.getParameter("username");
	request.setAttribute("username",username);	//设置请求参数
	System.out.println("用户名:"+username);	
	return "/WEB-INF/jsp/success.jsp";	//返回String类型，代表逻辑视图
}	

@RequestMapping("/test_model.action")
public String controller04(HttpServletRequest request,Model model) throws Exception{
	request.setCharacterEncoding("utf-8");
	String username = request.getParameter("username");
	model.addAttribute("username", username);	//等价于request.setAttribute(attrName,attrValue);
	System.out.println("用户名:"+username);
	return "/WEB-INF/jsp/success.jsp";	//返回String类型，跳转到逻辑视图
}

@RequestMapping("/test_redirect.action")
public String controller05(HttpServletRequest request) throws Exception{
	request.setCharacterEncoding("utf-8");
	String username = request.getParameter("username");
	User u = new User();
	u.setUsername(username);
	userService.insertUser(u);
	request.setAttribute("username",username);	//由于是redirect，所以请求参数失效
	return "redirect:/controller/test_model.action";//redirect：重定向到一个Controller里
}

@RequestMapping("/test_forword.action")
	public String controller06(HttpServletRequest request) throws Exception{
	request.setCharacterEncoding("utf-8");
	String username = request.getParameter("username");
	User u = new User();
	u.setUsername(username);
	userService.insertUser(u);
	System.out.println("用户名:"+username);
	request.setAttribute("username",username);	//由于是转发，所以请求参数有效
	return "forward:/controller/test_model.action";//转发，跳转到一个Controller里
}

参数绑定

参数绑定的第一种方法：绑定普通类型

//参数绑定的第一种方法：客户端提交的请求的input的name属性会和Controller方法的参数名字一致才会绑定
@RequestMapping("/test_parambinding01.action")
public void controller07(HttpServletRequest request,HttpServletResponse response,String username,String password) throws Exception{
	//必须进行转码
	username = new String(username.getBytes("iso8859-1"),"UTF-8");
	request.setAttribute("username",username);
	request.getRequestDispatcher("/WEB-INF/jsp/success.jsp").forward(request, response);	
}

//参数绑定的第二种方法:客户端的input标签的那么属性必须和User的属性名对应才可以映射成功
@RequestMapping("/test_parambinding02.action")
public ModelAndView controller08(HttpServletRequest request,User user) throws Exception{
	//必须进行转码
	user.setUsername(new String(user.getUsername().getBytes("iso-8859-1"),"utf-8"));
	userService.insertUser(user);
	ModelAndView modelAndView = new ModelAndView();
	request.setCharacterEncoding("utf-8");
	modelAndView.addObject("username",user.getUsername());
	modelAndView.addObject("password",user.getPassword());
	modelAndView.setViewName("/WEB-INF/jsp/success.jsp");
	return modelAndView;
}

@RequestMapping("test_RequestParam.action")
//将客户端的请求参数"username"与"uname"绑定
public ModelAndView controller09(@RequestParam(value="username") String uname,@RequestParam(value="password")String pwd) throws Exception{
	uname = new String(uname.getBytes("iso-8859-1"),"utf-8");	
	ModelAndView modelAndView = new ModelAndView();
	modelAndView.addObject("username",uname);
	modelAndView.setViewName("/WEB-INF/jsp/success.jsp");
	return modelAndView;
}