HttpClient如何发送post请求调用接口呢?

实现思路:
    1.使用maven引入相应的jar包
	2.使用setEntity即可将参数信息放入

引入jar包

<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpclient</artifactId>
	<version>4.1.2</version>
</dependency>
<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpclient-cache</artifactId>
	<version>4.1.2</version>
</dependency>
<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpmime</artifactId>
	<version>4.1.2</version>
</dependency>

编写相应的示例代码

  
/**
     * post请求
     * @param url    请求地址
     * @param b    设置到body中的参数字节数组
     * @param map    参数map
     * @return    返回接口字符串
     * @throws Exception
     */
    public static String httpPost(String url, byte[] b, Map<String, String> map) throws Exception {
        // 返回body
        String body = "";
        // 1、创建一个htt客户端
        HttpClient httpClient = new DefaultHttpClient();
        // 2、创建一个HttpPost请求
        HttpPost post = new HttpPost(url);
        post.setHeader("Content-Type", "application/x-www-form-urlencoded");
        post.setHeader("charset", "UTF-8");
        post.setEntity(new StringEntity("image=" + Base64AndUrlEncodeBytes(b)));
        // 5、设置header信息
        post.setHeader("X-Appid", APPID);
        post.setHeader("X-CurTime", getUTCTimeStr());
        post.setHeader("X-Param", Base64String(param));
        post.setHeader("X-CheckSum", MD5String(APIKey + getUTCTimeStr() + Base64String(param)));
        // post.setHeader("Connection", "close");
        // 设置参数
        if (map != null) {
            list<NameValuePair> pairs = new ArrayList<NameValuePair>();
            for (Map.Entry<String, String> entry : map.entrySet()) {
                pairs.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
            }
            post.setEntity(new UrlEncodedFormEntity(pairs, "UTF-8"));
        }
        // 7、执行post请求操作，并拿到结果
        HttpResponse httpResponse = httpClient.execute(post);
        // 获取结果实体
        HttpEntity entity = httpResponse.getEntity();
        if (entity != null) {
            // 按指定编码转换结果实体为String类型
            body = EntityUtils.toString(entity, HTTP.UTF_8);
        }
        // EntityUtils.consume(entity);
        httpClient.getConnectionManager().shutdown();
        System.out.println(body.length());
        return body;
    }