httpClient的post方法使用form格式数据调用接口

Http使用post调用接口，接口只接受form表单数据格式问题？

这个问题的关键是form表单提交的是数据格式是什么样子的，使用httpClient工具类时Header信息如何写。

会影响解决问题思路的因素：

1、         一致以来都是使用json数据格式调用接口的，form表单是什么格式一时向不起来。

2、         使用form表单数据情况，多是在前台页面使用form表单提交，或使用JavaScript中的FormData对象处理提交。如果是后台httpClient工具接口如何提交

解决思路：

1、先百度看网上怎么说的，找到一个有用的帖子：https://www.cnblogs.com/zhang-can/p/7631262.html 中有一句：

ajax发送的data是个字典，是键值对的形式，在http的post请求过程中，把这种键值对转换成

k1=xxx&k2=xxx这种格式，并且会带上一个请求头：

content-type : application/x-www-form-urlencoded

2、 前台访问后台实际实现也是http协议，那使用谷歌的调试工具，模拟一个form表单提交看看请求header和Form Data的情况：

点击“view source”显示的格式：

这是我们熟悉的格式。

根据上面的测试，修改httpClient的post工具类：

关键的地方是：post请求的Header设置

httpPost.addHeader("Content-type", "application/x-www-form-urlencoded; charset=utf-8");

在post中的参数格式为：param1=小明&param2=12

调用时实例：

HttpRequestUtil.post(url地址
        , “param1=小明&param2=12”);

测试结果：

返回参数：{"data":{},"code":"0","msg":"处理成功"}

工具类代码：

 import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
 import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.nio.charset.Charset;

 /**
  * Created by guoyanan on 2018/8/7 0007.
  * 接口调用工具类
  */
 public class HttpRequestUtil {
     private static CloseableHttpClient httpClient;

     static {
         PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
         cm.setMaxTotal(100);
         cm.setDefaultMaxPerRoute(20);
         cm.setDefaultMaxPerRoute(50);
         httpClient = HttpClients.custom().setConnectionManager(cm).build();
     }

     public static String get(String url) {
         CloseableHttpResponse response = null;
         BufferedReader in = null;
         String result = "";
         try {
             HttpGet httpGet = new HttpGet(url);
             RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();
             httpGet.setConfig(requestConfig);
             httpGet.setConfig(requestConfig);
             httpGet.addHeader("Content-type", "application/json; charset=utf-8");
             httpGet.setHeader("Accept", "application/json");
             response = httpClient.execute(httpGet);
             in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
             StringBuffer sb = new StringBuffer("");
             String line = "";
             String NL = System.getProperty("line.separator");
             while ((line = in.readLine()) != null) {
                 sb.append(line + NL);
             }
             in.close();
             result = sb.toString();
         } catch (IOException e) {
             e.printStackTrace();
         } finally {
             try {
                 if (null != response) {
                     response.close();
                 }
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return result;
     }

     public static String post(String url, String jsonString) {
         CloseableHttpResponse response = null;
         BufferedReader in = null;
         String result = "";
         try {
             HttpPost httpPost = new HttpPost(url);
             RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();
             httpPost.setConfig(requestConfig);
             httpPost.setConfig(requestConfig);
             httpPost.addHeader("Content-type", "application/x-www-form-urlencoded; charset=utf-8");
             httpPost.setHeader("Accept", "application/json");
             httpPost.setEntity(new StringEntity(jsonString, Charset.forName("UTF-8")));

             response = httpClient.execute(httpPost);
             in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
             StringBuffer sb = new StringBuffer("");
             String line = "";
             String NL = System.getProperty("line.separator");
             while ((line = in.readLine()) != null) {
                 sb.append(line + NL);
             }
             in.close();
             result = sb.toString();
         } catch (IOException e) {
             e.printStackTrace();
         } finally {
             try {
                 if (null != response) {
                     response.close();
                 }
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return result;
     }

 }