SpringMVC接收多个对象参数

朱雀 2023-07-09 12:27 186阅读 0赞

> 为了能够在controller中获取多个对象，我定义了两个@RequestBody的参数，结果报错：  
> I/O error while reading input message; nested exception is java.io.IOException: Stream closed  
> 只用一个@RequestBody参数，另外一个参数用@RequestParam，则controller接收到的参数都为null。  
> 于是引出了接下来的话题，SpringMVC如何接收多个对象参数？

### 1、定义包装类，使用包装类对象 ###

定义三个类，其中一个为包装类

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;
        }
    }

controller方法

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

前端代码

$("#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);                          
                           }
                       });
                    });

### 2、使用Map对象接收 ###

@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";
        }

### 3、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);                          
                       }
                   });
                });

转载自：  
https://blog.csdn.net/pozhenzi9010/article/details/80559186