一、Java后台POST请求以application/x-www-form-urlencoded;

1、引入依赖：

<dependency>
    <groupId>commons-httpclient</groupId>
    <artifactId>commons-httpclient</artifactId>
    <version>3.1</version>
</dependency>

2、写入代码：

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.PostMethod;
 
 
private String post(String postURL,String name,String age) throws Exception{
	PostMethod postMethod = new PostMethod(postURL) ;
	postMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8") ;
	//参数设置，需要注意的就是里边不能传NULL，要传空字符串
	NameValuePair[] data = {
		new NameValuePair("name",name),
		new NameValuePair("age",age)
	};
	postMethod.setRequestBody(data);
    org.apache.commons.httpclient.HttpClient httpClient = new org.apache.commons.httpclient.HttpClient();
	httpClient.executeMethod(postMethod);
	String result = postMethod.getResponseBodyAsString() ;
	return result;
}

二、Java后台POST请求raw的JSON的请求方式

1、写入代码：

   //发送请求
        HttpHeaders headers = new HttpHeaders();
        headers.add("Content-Type","application/json");

        Map<String,Object> map = new HashMap<>();
        map.put("logitcsInterface",encryptStr);
        map.put("apiCode","030001");
        map.put("senderNo","1030005864872");
        map.put("timeStamp",DateUtil.dataToStr(new Date()));
        map.put("authorization","UZCCFaqJZTHV151C50");

        HttpEntity<String> formEntity = new HttpEntity<>(map.toString(), headers);
        RestTemplate restTemplate = new RestTemplate();
        String urlAdress = "https://api.ems.com.cn/amp-prod-api/f/amp/api/test";//请求地址
        ResponseEntity<String> responseEntity = restTemplate.postForEntity(urlAdress, formEntity, String.class);
        String jsonData = responseEntity.getBody();
        System.out.println(jsonData);

三、java实现postman中form-data传参方式

然后上次在用java实现一个向后台传参的形式时，在postman里以form-data的形式传参，我就尝试利用map进行数据的的封装Map<String,String>，结果发现后台无法正确解析参数。是因为map封装后并不是以&链接的。需要传递的参数和参数形式如下所示：

 利用spring来作为后端框架，form-data利用LinkedMultiValueMap对象来包装多个参数，参数以key-value形式，中间以&连接。利用java代码的实现如下：

public ResponseData baseApi(String methodArg,String bizContent){
        if(methodArg == null || methodArg.equals("")){
            ResponseData responseData = new ResponseData(false,"the param methodArg is null","");
            return responseData;
        }
        if(bizContent == null || bizContent.equals("")){
            ResponseData responseData = new ResponseData(false,"the param bizContent is null","");
            return responseData;
        }
            String apiUrl = Contants.publicUrl  +"/"+ methodArg;
            HttpHeaders headers = new HttpHeaders();
            MultiValueMap<String, String> map= new LinkedMultiValueMap<>();
            headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
            map.add("app_id", Contants.clientId);
            map.add("method",methodArg);
            map.add("format","json");
            map.add("charset","utf-8");
            map.add("timestamp",Contants.timeStamp);
            map.add("token",Contants.accessToken);
            map.add("biz_content",bizContent);
            HttpEntity<MultiValueMap<String, String>> requestParams = new HttpEntity<>(map, headers);
            ResponseEntity<String> response = restTemplate.postForEntity(apiUrl,requestParams,String.class);
            String result =response.getBody();
            JSONObject jsStr = JSONObject.parseObject(result);
            String resultCode = jsStr.getString("code");

            if(Integer.parseInt(resultCode)!= 0){
                ResponseData responseData = new ResponseData(false,"error",result);
                return responseData;
            }

            ResponseData responseData = new ResponseData(true,"success",result);
            return responseData;
    }

详细了解postman的几种调用方式可参考：

java实现postman中form-data传参方式_postman formdata_程可爱的博客-CSDN博客