Three ways in which spring MVC returns JSON data

One. Return Modelandview, which contains the map set

/** Returns the result of the Modelandview type * Checks the legality of the user name, returns False if the user already exists, otherwise returns True (returns the JSON data in the format {"Valid", true})*/@RequestMapping (Value= "/checknameexistsmethod2", produces = "application/json;charset=utf-8")//the produces value here is automatically determined by the return result if not set.     Public@ResponseBody modelandview checkNameValidMethod2 (@RequestParam String name) {Booleanresult =true; //...map<string, boolean> map =NewHashmap<>(); Map.put ("Valid", result); return NewModelandview (NewMappingjackson2jsonview (), map); }

Two. Returns JSON of type string

    /** Returns the result of string type * Check the legality of user name, return False if user already exists, otherwise return True (return JSON data, format {"Valid", true})*/@RequestMapping (Value= "/checknameexistsmethod1", produces = "Application/json;charset=utf-8")     Public@ResponseBody string checkNameValidMethod1 (@RequestParam string name) {Booleanresult =true; //...Map.put ("valid", result); Objectmapper Mapper=NewObjectmapper (); String resultstring= ""; Try{resultstring=mapper.writevalueasstring (map); } Catch(jsonprocessingexception e) {e.printstacktrace (); }        returnresultstring; }

Three. Returns the result of any predefined class type:

@RequestMapping (value = "/findemployeebyname")    public  @ResponseBody    Employee Findemployeebyname (String name) {        List<Employee> lstemployees = employeeservice.getallemployees ( );          for (Employee employee:lstemployees) {            if  (Employee.getname (). Equals (name))                 return employee;        }         return NULL ;    }

The employ here must be defined beforehand.

Three ways in which spring MVC returns JSON data