【一】、封裝HttpClient和Json解析

封裝HttpClient和Json解析（這裏主要介紹封裝的思想，具體的代碼實現我會在github中給出）

在實際開發中，我們可能需要調用第三方服務器的接口，這就要使用到HttpClient來發送請求，這裏就基於HttpClient封裝了比較方便的助手類，並且擴展封裝了響應信息的格式化（目前只支持Json格式化，開發者可以自定義格式化方法）

1.首先引入相關的依賴包：

<!--https://mvnrepository.com/artifact/com.alibaba/fastjson-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.29</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.3</version>
</dependency>

2.目前爲止整個工程的目錄如下：

這裏爲了日後擴展，使用了接口的思想，需要解析不同格式的字符串時，只需要在方法中傳入解析接口ResponseParser的實現類，自定義具體的解析算法即可，並不需要在原來的代碼上修改。

使用方法也很簡單，調用的代碼如下：

public void testPostRawData2Str() {
    Map<String, Object> reqParams = new HashMap<>();
    reqParams.put("id", UUID.randomUUID().toString());

    Map<String, Object> res = HttpClientHelper.postRawData(url, reqParams);
    System.out.println(res);
}

最終返回的是一個map集合的結果。

源代碼我也在github上面給出：

https://github.com/wulongtao/web-base-master/tree/master/src/main/java/com/xxh/web/util/http

https://github.com/wulongtao/web-base-master/tree/master/src/main/java/com/xxh/web/util/format

主要代碼如下：

package com.xxh.web.util.http;

import com.alibaba.fastjson.JSONObject;
import com.xxh.web.util.format.JsonResponseParser;
import com.xxh.web.util.format.ResponseParser;
import org.apache.http.HttpEntity;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.Map;

/**
 * HttpClient助手類，主要實現了請求響應數據的格式化，方便開發調用
 * Created by wulongtao on 2017/5/15.
 */
public class HttpClientHelper {
    private static final Logger logger = LoggerFactory.getLogger(HttpClientHelper.class);
    private static ResponseParser responseParser = new JsonResponseParser();

    /**
     * 以rawData形式發送http post請求，Map集合方式返回
     * @param url url
     * @param reqParams 請求參數
     * @return
     */
    public static Map<String, Object> postRawData(String url, Map<String, Object> reqParams) {
        String resp = postRawData2Str(url, reqParams);
        return responseParser.parse(resp);
    }

    /**
     * * 以rawData形式發送http post請求，Map集合方式返回
     * @param url url
     * @param reqParams 請求參數
     * @param responseParser ResponseParser的實現類，實現parse方法
     * @return
     */
    public static Map<String, Object> postRawData(String url, Map<String, Object> reqParams, ResponseParser responseParser) {
        String resp = postRawData2Str(url, reqParams);
        return responseParser.parse(resp);
    }

    /**
     * 以rawData形式發送http post請求，字符串形式返回響應結果
     * @param url url
     * @param reqParams 請求參數
     * @return
     */
    public static String postRawData2Str(String url, Map<String, Object> reqParams) {
        String resp = "";

        StringEntity entityStr = new StringEntity(JSONObject.toJSONString(reqParams), ContentType
                .create("text/plain", "UTF-8"));

        CloseableHttpClient httpClient = HttpClients.createDefault();

        HttpPost httpPost = new HttpPost(url);
        httpPost.setEntity(entityStr);
        CloseableHttpResponse response = null;

        try {
            response = httpClient.execute(httpPost);

            //logger
            logger.info("Do post raw data,status line=" + response.getStatusLine());


            HttpEntity entity = response.getEntity();
            resp = EntityUtils.toString(entity, "UTF-8");
            EntityUtils.consume(entity);
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }

        if (resp == null || resp.equals("")) {
            return "";
        }

        return resp;
    }
}

package com.xxh.web.util.format;

import java.util.Map;

/**
 * Created by wulongtao on 2017/5/16.
 */
public interface ResponseParser {
    /**
     * 解析http響應消息，可以擴展解析JSON、XML等格式
     * @param resp
     * @return
     */
    Map<String, Object> parse(String resp);
}

package com.xxh.web.util.format;

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import java.util.*;

/**
 * Created by wulongtao on 2017/5/16.
 */
public class JsonResponseParser implements ResponseParser {

    @Override
    public Map<String, Object> parse(String resp) {
        JSONObject jsonObject = JSONObject.parseObject(resp);
        return parseFromJson(jsonObject);
    }

    /**
     * 根據JSONObject對象解析成Map對象
     * @param jsonObject
     * @return
     */
    private Map<String, Object> parseFromJson(JSONObject jsonObject) {
        Map<String, Object> mRes = new HashMap<>();
        Iterator<Map.Entry<String, Object>> it = jsonObject.entrySet().iterator();

        while (it.hasNext()) {
            Map.Entry<String, Object> param = it.next();

            if (param.getValue() instanceof JSONObject) {
                mRes.put(param.getKey(), parseFromJson((JSONObject) param.getValue()));
            } else if (param.getValue() instanceof JSONArray) {
                mRes.put(param.getKey(), json2List(param.getValue()));
            } else {
                mRes.put(param.getKey(), param.getValue());
            }
        }
        return mRes;
    }

    private List<Map<String, Object>> json2List(Object json) {
        JSONArray arrJson = (JSONArray) json;

        List<Map<String, Object>> lst = new ArrayList<>();
        for (int i = 0; i < arrJson.size(); i++) {

            lst.add(parseFromJson(arrJson.getJSONObject(i)));
        }

        return lst;
    }
}