httpclient 带参数 post get

桃扇骨 2022-04-22 08:54 186阅读 0赞

### httpclient 带参数 post get ###

//httpclient 和httpcore的maven依赖包
     <dependencies>
    	  	<dependency>
    			<groupId>org.apache.httpcomponents</groupId>
    			<artifactId>httpclient</artifactId>
    			<version>4.5.2</version>
    		</dependency>
    		<dependency>
    			<groupId>org.apache.httpcomponents</groupId>
    			<artifactId>httpcore</artifactId>
    			<version>4.4.6</version>
    		</dependency>
      </dependencies>

#### post方法 ####

//带参数的post方法
    String getTokenUr = prop.getProperty("ys.GetTokenUrl");
    //        创建httpclient对象
            CloseableHttpClient client = HttpClients.createDefault();
    //        创建httppost 对象
            HttpPost httpPost = new HttpPost(getTokenUr);
            //设置header信息
            //指定报文头【Content-type】、【User-Agent】
            httpPost.setHeader("Content-type", "application/x-www-form-urlencoded");
            /**
             * 获取萤石信息
             */
            String appkey = prop.getProperty("ys.AppKey");
            String secret = prop.getProperty("ys.Secret");
    
            List<NameValuePair> list = new ArrayList<NameValuePair>();
            list.add(new BasicNameValuePair("appKey", appkey));
            list.add(new BasicNameValuePair("appSecret", secret));
            try {
                UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(list);
                httpPost.setEntity(formEntity);
                CloseableHttpResponse response = client.execute(httpPost);
                HttpEntity entity = response.getEntity();
                String str = EntityUtils.toString(entity, "UTF-8");
                JSONObject jsonObject = JSONObject.fromObject(str);
                prop.setProperty("ys.Token", (String) JSONObject.fromObject(jsonObject.get("data")).get("accessToken"));
                URL confUri = this.getClass().getResource("/conf.properties");
                FileOutputStream fos = new FileOutputStream(new File(confUri.toURI()));
                prop.store(fos, "new token");
                response.close();
            } catch (UnsupportedEncodingException e) {
                logger.log(-1, e.getMessage());
            } catch (ClientProtocolException e) {
                logger.log(-1, e.getMessage());
            } catch (IOException e) {
                logger.log(-1, e.getMessage());
            } catch (URISyntaxException e) {
                e.printStackTrace();
            }

#### get方法 ####

// 获取http客户端
    		CloseableHttpClient client = HttpClients.createDefault();
    		// 通过httpget方式来实现我们的get请求
    		HttpGet httpGet = new HttpGet("YOUR URL");
    		// 通过client调用execute方法，得到我们的执行结果就是一个response，所有的数据都封装在response里面了
    		CloseableHttpResponse Response = client.execute(httpGet);
    		// HttpEntity
    		// 是一个中间的桥梁，在httpClient里面，是连接我们的请求与响应的一个中间桥梁，所有的请求参数都是通过HttpEntity携带过去的
    		// 所有的响应的数据，也全部都是封装在HttpEntity里面
    		HttpEntity entity = Response.getEntity();
    		// 通过EntityUtils 来将我们的数据转换成字符串
    		String str = EntityUtils.toString(entity, "UTF-8");
    		// EntityUtils.toString(entity)
    		System.out.println(str);
    		// 关闭
    		Response.close();

**常见错误说明**

> Exception in thread “main” java.lang.NoSuchFieldError: INSTANCE  
> 当出现这种信息的时候是因为项目里有两个httpClient.jar包，编译器默认使用版本低的包，在获取连接的时候发现这个错误，检查jar包的时候才发现，在lib目录下有一个httpClient4.0的包，将其删除即可。