服务端请求的url
HttpPost post = new HttpPost("http://localhost:9091/receive/"+receiverIdParam);
客户端的接口
@PostMapping("/receive/{id}")
public Result receive(HttpServletRequest request,
@RequestParam("file") MultipartFile file,
@PathVariable("receiverIdParam") String receiverIdParam){
目前出现这个问题
@Pathvariable Required URI template variable 'receiverIdParam' for method parameter type String is not present]
@PostMapping("/receive/{id}")中{}里面的变量名，与@PathVariable("receiverIdParam")中的名称要一致。
不知道你这个问题是否已经解决, 如果还没有解决的话:基于springboot项目，添加httpclient依赖；
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
</dependency>
GET请求
不管怎么说，步骤里肯定有创建HttpClient对象，HttpGet对象，Params请求参数（有参的情况下）；尤其是Params的添加，因为大家需求不同，需要传的参数以及类型不同，对于参数的封装方式就有不同；
public static String sendGetForm(String url, Map<String, String> params) {
try (CloseableHttpClient httpClient = HttpClients.createDefault()){
String param = "";
if (params != null) {
Set<Entry<String, String>> set = params.entrySet();
for(Entry<String, String> entry : set) {
if(param.isEmpty()) {
param = entry.getKey() + "=" + entry.getValue();
}else {
param = param + "&" + entry.getKey() + "=" + entry.getValue();
}
}
}
url = param.isEmpty() ? url : url + "?" + param;
HttpGet httpGet = new HttpGet(url);
try(CloseableHttpResponse response = httpClient.execute(httpGet)){
return EntityUtils.toString(response.getEntity(), "utf-8");
}
} catch (Exception e) {
log.error("发送get请求失败", e);
throw new RuntimeException("发送get请求失败", e);
}
}
简单介绍一下吧：
创建httpClient，至于为什么声明的CloseableHttpClient 类，这个类可以在我们请求完自动释放连接；
CloseableHttpClient httpClient = HttpClients.createDefault()
下面定义param参数配置到url后
这样请求参数可有可无，并且参数放到url后需要的格式；
创建httpGet请求对象
HttpGet httpGet = new HttpGet(url);
发送请求，接收响应（配置响应体）
CloseableHttpResponse response = httpClient.execute(httpGet)
POST请求
POST请求又不一样啦，因为它有请求体可以传各种类型的数据（content-type）
看了一下公司封装好的post请求，真的好多种，根据你要传的参数不同，需要配置的请求头、请求体就有所不同；所以在我们使用发送方法前要提前明白自己需要传什么样的数据，这样也就知道需要如何封装请求参数；、
对于返回的请求结果response后面的，一般就是将获取到的响应体进行一个编码，防止中文乱码等；
//Post方式表单提交
public static String sendPostForm(String url, Map<String, String> params) {
try (CloseableHttpClient httpClient = HttpClients.createDefault()){
HttpPost httpPost = new HttpPost(url);
if (params != null) {
List<NameValuePair> nameValuePairs = new ArrayList<>();
for (String key : params.keySet()) {
nameValuePairs.add(new BasicNameValuePair(key, params.get(key)));
}
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(nameValuePairs);
httpPost.setEntity(entity);
}
try(CloseableHttpResponse response = httpClient.execute(httpPost)){
return EntityUtils.toString(response.getEntity(), "utf-8");
}
} catch (Exception e) {
log.error("发送post请求失败", e);
throw new RuntimeException("发送post请求失败", e);
}
}
//发送json格式数据
public static String sendPostJson(String url, String json) {
try (CloseableHttpClient httpClient = HttpClients.createDefault()){
HttpPost httpPost = new HttpPost(url);
StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
httpPost.setEntity(entity);
try(CloseableHttpResponse response = httpClient.execute(httpPost)){
return EntityUtils.toString(response.getEntity(), "utf-8");
}
} catch (Exception e) {
log.error("发送post请求失败", e);
throw new RuntimeException("发送post请求失败", e);
}
}
艰难介绍一下：
NameValuePair类型，叫做简单名称值对节点类型，就是请求数据中要求的参数类型吧；content-type 也就不同。
还有一个就是通过post请求发送文件：
private String sendFile( String url,MultipartFile file,HashMap<String,String> map) throws IOException {
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPost httpPost = new HttpPost(url);
String rspMsg =null;
MultipartEntityBuilder params = MultipartEntityBuilder.create();
//定义post请求的请求数据类型
ContentType strContent = ContentType.create(ContentType.MULTIPART_FORM_DATA.getMimeType(),Consts.UTF_8);
//将文件放到请求体中
params.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());
//添加需要发送的普通参数
params.addTextBody("waterno",map.get("waterno"),strContent);
params.addTextBody("cutwatertone",map.get("cutwatertone"),strContent);
HttpEntity httpEntity = params.build();
httpPost.setEntity(httpEntity);
try {
StringBuilder sb = new StringBuilder();
String line;
HttpResponse httpResponse = httpclient.execute(httpPost);
InputStream inputStream = httpResponse.getEntity().getContent();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream,"UTF-8"));
while ((line = br.readLine()) != null) {
sb.append(line);
}
rspMsg = URLDecoder.decode(sb.toString(),"UTF-8");
} catch (Exception e) {
e.printStackTrace();
}
return rspMsg;
}
对于这个发送文件的封装方法，网上真的很多，但有些就是封装了file的参数，没有其他普通参数的封装，还有要主要的就是发送文件必须要把文件转换成流才行。当时做发送文件和参数到电信接口时，就在网上找了好多好多方法，都不行…；其实这也是再网上找的，不同的是在创建请求体时，使用的是一个创建者设计模式，有点绕。但是大致步骤还是一样的。