Optional type of SPRINGMVC Controller return value

Spring MVC supports the following return methods: Modelandview, Model, Modelmap, Map,view, String, void.

Modelandview

@RequestMapping ("/hello") public    Modelandview HelloWorld () {         String message = ' Hello world, Spring 3.x! ';        return new Modelandview ("Hello", "message", message);    }

The Modelandview construction method allows you to specify the name of the page returned, or you can jump to the specified page by using the Setviewname () method.

Map

@RequestMapping ("/demo2/show") public     map<string, string> getmap () {         map<string, string> Map = new Hashmap<string, string> ();         Map.put ("Key1", "value-1");         Map.put ("Key2", "value-2");         return map;     

The value can be obtained straight through ${key1} in the JSP page, and Map.put () is equivalent to the Request.setattribute method.

View

You can return to PDF Excel, etc., for the time being without detailed information.

String

Specifies the name of the returned view page, combined with the return address path set and the page name suffix to access.
Note: If the method declares annotation @responsebody, the return value is output directly to the page.

@RequestMapping (value= "/showdog") public    String Hello1 () {        return "Hello";    }

@RequestMapping (value= "/print")    @ResponseBody public    String print () {        string message = ' Hello world ' Spring mvc! ";        return message;    }

Return to the JSON example (using Jackson):

@RequestMapping ("/load1")    @ResponseBody public    string Load1 (@RequestParam string name, @RequestParam string Password) throws ioexception{        System.out.println (name+ ":" +password);          Return name+ ":" +password;        Mydog dog=new Mydog ();        Dog.setname ("Xiao Ha");d og.setage ("1 years old");d Og.setcolor ("dark grey");        Objectmapper objectmapper = new Objectmapper ();        String jsonstring=objectmapper.writevalueasstring (dog);        System.out.println (jsonstring);        return jsonstring;    }

void

If the return value is empty, the Response view page corresponds to the access address

@RequestMapping ("/index") public    Void Index () {        return;    }

The corresponding logical view is named "Index".

Summary:
1. The return value type using String as the request processing method is a more general method, so the returned logical view name does not bind to the request URL, and the model data can be controlled by Modelmap.
2. When using Void,map,model, return the corresponding logical view name real URL is: prefix prefix + view name +suffix suffix.
3. Using String,modelandview to return the view name can be not bound by the requested URL, Modelandview can set the returned view name.

Optional type of SPRINGMVC Controller return value