springboot解决传递json字符串时获取某个参数为null

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 {
Reques
4000
tJson 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

package com.pb.news;

import com.pb.news.annotation.RequestJsonHandlerMethodArgumentResolver;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import java.util.List;

@Configuration
public class webConfig extends WebMvcConfigurerAdapter {

/*配置自定义接受参数的方法*/

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