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;
    }

}