springboot解决传递json字符串时获取某个参数为null

最新推荐文章于 2025-07-11 23:01:47 发布

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最新推荐文章于 2025-07-11 23:01:47 发布

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本文介绍了使用Postman进行数据传递的多种方式，包括实体自动转换、Map或JSON接收及自定义接收方法。此外，还详细讲解了如何通过自定义注解实现特定参数的接收。

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当postman传递数据时，如此有多个解决方案，如：

1.以自动转换实体

@RequestMapping(value="/getAjax",method = RequestMethod.POST)
    @ResponseBody
    public void getAjax(@RequestBody News news){
        System.out.println("ok");
    }

2.以map或json接收

    @RequestMapping(value="/login2",method = RequestMethod.POST)
    @ResponseBody
    public  void login2(@RequestBody JSONObject jsonObject){
        System.out.println("ok");
    }

3.新建一个自定义接收方式

@RequestMapping(value="/login3",method = RequestMethod.POST)
    public  void login3(@RequestJson(value = "name") String name,@RequestJson(value = "pwd") String pwd){
        System.out.println("ok");
    }

以下是代码：

创建以上两个文件：

1.RequestJson

package com.pb.news.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RequestJson {
    String value();
}

2.RequestJsonHandlerMethodArgumentResolver

package com.pb.news.annotation;

import java.io.BufferedReader;
import javax.servlet.http.HttpServletRequest;
import org.springframework.core.MethodParameter;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
import com.alibaba.fastjson.JSONObject;

public class RequestJsonHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {
    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.hasParameterAnnotation(RequestJson.class);
    }


    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
                                  NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
        RequestJson requestJson = parameter.getParameterAnnotation(RequestJson.class);
        HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
        BufferedReader reader = request.getReader();
        StringBuilder sb = new StringBuilder();
        char[] buf = new char[1024];
        int rd;
        while ((rd = reader.read(buf)) != -1) {
            sb.append(buf, 0, rd);
        }
        JSONObject jsonObject = JSONObject.parseObject(sb.toString());
        String value = requestJson.value();
        return jsonObject.get(value);
    }
}

最后，新建一个webConfig添加该方法

@Override public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers){ argumentResolvers.add(new RequestJsonHandlerMethodArgumentResolver()); }}

补充：

如果只想传递某一个参数时：这种情况，因为是RequestParam，所以采用表单的方式传递

@RequestMapping(value="/userLogin",method = RequestMethod.POST)
    @ResponseBody
    //@ApiImplicitParam(paramType = "query",name= "username" ,value = "用户名",dataType = "string")
    public  void userLogin(@RequestParam(value = "username" , required = false) String username,
                           @RequestParam(value = "password" , required = false) String password){