springMVC Controller接收多对象的json数据

àì夳堔傛蜴生んèń 2023-06-24 03:49 25阅读 0赞

[ ![20191216172544126.png][] ][_20191216172544126.png_]

**第一种方法，用包装类封装对象**

实体类对象

public class User { 
         
         private int id; 
         private String userName; 
         private String realName; 
         
         public int getId() { 
         return id; 
         } 
         
         public void setId(int id) { 
         this.id = id; 
         } 
         
         public String getUserName() { 
         return userName; 
         } 
         
         public void setUserName(String userName) { 
         this.userName = userName; 
         } 
         
         public String getRealName() { 
         return realName; 
         } 
         
         public void setRealName(String realName) { 
         this.realName = realName; 
         } 
         
         @Override 
         public String toString() { 
         return "User{" + 
         "id=" + id + 
         ", userName='" + userName + '\'' + 
         ", realName='" + realName + '\'' + 
         '}'; 
         } 
         } 
         
         
         public class Info { 
         
         private int id; 
         private String address; 
         
         public int getId() { 
         return id; 
         } 
         
         public void setId(int id) { 
         this.id = id; 
         } 
         
         public String getAddress() { 
         return address; 
         } 
         
         public void setAddress(String address) { 
         this.address = address; 
         } 
         
         @Override 
         public String toString() { 
         return "Info{" + 
         "id=" + id + 
         ", address='" + address + '\'' + 
         '}'; 
         } 
         } 
         
         public class RequestParam { 
         
         private User user; 
         
         private Info info; 
         
         public User getUser() { 
         return user; 
         } 
         
         public void setUser(User user) { 
         this.user = user; 
         } 
         
         public Info getInfo() { 
         return info; 
         } 
         
         public void setInfo(Info info) { 
         this.info = info; 
         } 
         }

定义了三个实体 RequestParam里面又封装了User类和Info类

JAVA代码

@RequestMapping(value = "/show",method = RequestMethod.POST) 
         public String show(@RequestBody RequestParam param){ 
         
         User user = param.getUser(); 
         Info info = param.getInfo(); 
         
         return user.toString(); 
         }

前台代码

$("#ok2").click(function(){ 
         var json = {"user":{"id":9527,"userName":"zcy","realName":"钢铁侠"},"info":{"id":998,"address":"纽约"}}; 
         $.ajax({ 
         url:"http://localhost:8080/more/show", 
         type:"post", 
         cache:false, 
         contentType:"application/json", 
         data:JSON.stringify(json), 
         success:function(data){ 
         alert(data); 
         } 
         }); 
         });

可以成功接收到对象，但是显得没有那么优雅，每次请求数据不同都要另外写一个包装类，显得很麻烦。

**第二种方法，用Map对象接收 更加简单粗暴**

**JAVA代码**

@RequestMapping(value = "/show") 
         public String test(@RequestBody Map<String,Object> map){ 
         
         // 拿到Object之后 再做转换为实体即可 可以用FastJson 
         Object user = map.get( "user"); 
         Object info = map.get( "info"); 
         
         return "success"; 
         }

也不够方便 每个对象还要再做一次转换

第三种方法，使用自定义的HandlerMethodArgumentResolver

自定义注解 加在控制器的参数前作为标记

@Target(ElementType.PARAMETER) 
         @Retention(RetentionPolicy.RUNTIME) 
         @Documented 
         public @interface JsonObject { 
         }

自定义处理类 实现HandlerMethodArgumentResolver接口

public class JsonObjectArgResolverHandler implements HandlerMethodArgumentResolver { 
         
         @Override 
         public boolean supportsParameter(MethodParameter methodParameter) { 
         return methodParameter.hasParameterAnnotation(JsonObject.class); 
         } 
         
         @Override 
         public Object resolveArgument(MethodParameter methodParameter, 
         ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, 
         WebDataBinderFactory webDataBinderFactory) throws Exception { 
         
         // 获取Controller中的参数名 
         String name = methodParameter.getParameterName(); 
         // 获取Controller中参数的类型 
         Class clazz = methodParameter.getParameterType(); 
         Object arg = null; 
         // 获取该参数实体的所用属性 
         Field[] fields = clazz.getDeclaredFields(); 
         // 实例化 
         Object target = clazz.newInstance(); 
         
         // 创建WebDataBinder对象 反射 遍历fields给属性赋值 
         WebDataBinder binder = webDataBinderFactory.createBinder(nativeWebRequest, null,name); 
         for (Field field:fields){ 
         field.setAccessible( true); 
         String fieldName = field.getName(); 
         Class<?> fieldType = field.getType(); 
         // 在request中 多对象json数据的key被解析为 user[id] user[realName] info[address] 的这种形式 
         String value = nativeWebRequest.getParameter(name + "[" + fieldName + "]"); 
         arg = binder.convertIfNecessary(value,fieldType,methodParameter); 
         field.set(target,arg); 
         } 
         
         return target; 
         } 
         }

注册自己写的处理类

@Component 
         public class MyWebAppConfig implements WebMvcConfigurer { 
         
         
         @Override 
         public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) { 
         // 配置自定义接收参数 
         WebMvcConfigurer. super.addArgumentResolvers(resolvers); 
         resolvers.add( new JsonObjectArgResolverHandler()); 
         } 
         }

Controller

@RequestMapping(value = "/custom") 
         public String custom(@JsonObject User user, @JsonObject Info info){ 
         System.out.println(user.toString()); 
         System.out.println(info.toString()); 
         
         return "success"; 
         }

前台代码

$("#ok2").click(function(){ 
         var json = {"user":{"id":9527,"userName":"zcy","realName":"钢铁侠"},"info":{"id":998,"address":"纽约"}}; 
         $.ajax({ 
         url:"http://localhost:8080/more/custom", 
         type:"post", 
         cache:false, 
         // 直接传josn对象 这里与上文不同 
         data:json, 
         success:function(data){ 
         alert(data); 
         } 
         }); 
         });

第三种方式相对比较好 但我有几点还是没明白

public Object resolveArgument(MethodParameter methodParameter,
                                  ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest,
                                  WebDataBinderFactory webDataBinderFactory)

这个方法中的 ModelAndViewContainer和webDataBinderFactory 这两个对象的作用，怎样写能够优雅，欢迎大家不吝赐教。

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