使用HttpClient調用接口的實例講解

public class HttpResult {
// 響應的狀態碼
private int code;

// 響應的響應體
private String body;
get/set…
}

package cn.xxxxxx.httpclient;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class APIService {

 private CloseableHttpClient httpClient;

 public APIService() {
  // 1 創建HttpClinet，相當于打開瀏覽器
  this.httpClient = HttpClients.createDefault();
 }

 /**
  * 帶參數的get請求
  * 
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doGet(String url, Map<String, Object> map) throws Exception {

  // 聲明URIBuilder
  URIBuilder uriBuilder = new URIBuilder(url);

  // 判斷參數map是否為非空
  if (map != null) {
   // 遍歷參數
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    // 設置參數
    uriBuilder.setParameter(entry.getKey(), entry.getValue().toString());
   }
  }

  // 2 創建httpGet對象，相當于設置url請求地址
  HttpGet httpGet = new HttpGet(uriBuilder.build());

  // 3 使用HttpClient執行httpGet，相當于按回車，發起請求
  CloseableHttpResponse response = this.httpClient.execute(httpGet);

  // 4 解析結果，封裝返回對象httpResult，相當于顯示相應的結果
  // 狀態碼
  // response.getStatusLine().getStatusCode();
  // 響應體，字符串，如果response.getEntity()為空，下面這個代碼會報錯,所以解析之前要做非空的判斷
  // EntityUtils.toString(response.getEntity(), "UTF-8");
  HttpResult httpResult = null;
  // 解析數據封裝HttpResult
  if (response.getEntity() != null) {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(),
     EntityUtils.toString(response.getEntity(), "UTF-8"));
  } else {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(), "");
  }

  // 返回
  return httpResult;
 }

 /**
  * 不帶參數的get請求
  * 
  * @param url
  * @return
  * @throws Exception
  */
 public HttpResult doGet(String url) throws Exception {
  HttpResult httpResult = this.doGet(url, null);
  return httpResult;
 }

 /**
  * 帶參數的post請求
  * 
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doPost(String url, Map<String, Object> map) throws Exception {
  // 聲明httpPost請求
  HttpPost httpPost = new HttpPost(url);

  // 判斷map不為空
  if (map != null) {
   // 聲明存放參數的List集合
   List<NameValuePair> params = new ArrayList<NameValuePair>();

   // 遍歷map，設置參數到list中
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    params.add(new BasicNameValuePair(entry.getKey(), entry.getValue().toString()));
   }

   // 創建form表單對象
   UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "UTF-8");

   // 把表單對象設置到httpPost中
   httpPost.setEntity(formEntity);
  }

  // 使用HttpClient發起請求，返回response
  CloseableHttpResponse response = this.httpClient.execute(httpPost);

  // 解析response封裝返回對象httpResult
  HttpResult httpResult = null;
  if (response.getEntity() != null) {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(),
     EntityUtils.toString(response.getEntity(), "UTF-8"));
  } else {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(), "");
  }

  // 返回結果
  return httpResult;
 }

 /**
  * 不帶參數的post請求
  * 
  * @param url
  * @return
  * @throws Exception
  */
 public HttpResult doPost(String url) throws Exception {
  HttpResult httpResult = this.doPost(url, null);
  return httpResult;
 }

 /**
  * 帶參數的Put請求
  * 
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doPut(String url, Map<String, Object> map) throws Exception {
  // 聲明httpPost請求
  HttpPut httpPut = new HttpPut(url);

  // 判斷map不為空
  if (map != null) {
   // 聲明存放參數的List集合
   List<NameValuePair> params = new ArrayList<NameValuePair>();

   // 遍歷map，設置參數到list中
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    params.add(new BasicNameValuePair(entry.getKey(), entry.getValue().toString()));
   }

   // 創建form表單對象
   UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "UTF-8");

   // 把表單對象設置到httpPost中
   httpPut.setEntity(formEntity);
  }

  // 使用HttpClient發起請求，返回response
  CloseableHttpResponse response = this.httpClient.execute(httpPut);

  // 解析response封裝返回對象httpResult
  HttpResult httpResult = null;
  if (response.getEntity() != null) {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(),
     EntityUtils.toString(response.getEntity(), "UTF-8"));
  } else {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(), "");
  }

  // 返回結果
  return httpResult;
 }

 /**
  * 帶參數的Delete請求
  * 
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doDelete(String url, Map<String, Object> map) throws Exception {

  // 聲明URIBuilder
  URIBuilder uriBuilder = new URIBuilder(url);

  // 判斷參數map是否為非空
  if (map != null) {
   // 遍歷參數
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    // 設置參數
    uriBuilder.setParameter(entry.getKey(), entry.getValue().toString());
   }
  }

  // 2 創建httpGet對象，相當于設置url請求地址
  HttpDelete httpDelete = new HttpDelete(uriBuilder.build());

  // 3 使用HttpClient執行httpGet，相當于按回車，發起請求
  CloseableHttpResponse response = this.httpClient.execute(httpDelete);

  // 4 解析結果，封裝返回對象httpResult，相當于顯示相應的結果
  // 狀態碼
  // response.getStatusLine().getStatusCode();
  // 響應體，字符串，如果response.getEntity()為空，下面這個代碼會報錯,所以解析之前要做非空的判斷
  // EntityUtils.toString(response.getEntity(), "UTF-8");
  HttpResult httpResult = null;
  // 解析數據封裝HttpResult
  if (response.getEntity() != null) {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(),
     EntityUtils.toString(response.getEntity(), "UTF-8"));
  } else {
   httpResult = new HttpResult(response.getStatusLine().getStatusCode(), "");
  }

  // 返回
  return httpResult;
 }

}

package cn.xxxxxx.httpclient.test;

import java.util.HashMap;
import java.util.Map;

import org.junit.Before;
import org.junit.Test;

import cn.itcast.httpclient.APIService;
import cn.itcast.httpclient.HttpResult;

public class APIServiceTest {

 private APIService apiService;

 @Before
 public void init() {
  this.apiService = new APIService();
 }

 // 查詢
 @Test
 public void testQueryItemById() throws Exception {
  // http://manager.aaaaaa.com/rest/item/interface/{id}

  String url = "http://manager.aaaaaa.com/rest/item/interface/42";

  HttpResult httpResult = this.apiService.doGet(url);

  System.out.println(httpResult.getCode());
  System.out.println(httpResult.getBody());

 }

 // 新增
 @Test
 public void testSaveItem() throws Exception {
  // http://manager.aaaaaa.com/rest/item/interface/{id}

  String url = "http://manager.aaaaaa.com/rest/item/interface";

  Map<String, Object> map = new HashMap<String, Object>();
  // title=測試RESTful風格的接口&price=1000&num=1&cid=888&status=1
  map.put("title", "測試APIService調用新增接口");
  map.put("price", "1000");
  map.put("num", "1");
  map.put("cid", "666");
  map.put("status", "1");

  HttpResult httpResult = this.apiService.doPost(url, map);

  System.out.println(httpResult.getCode());
  System.out.println(httpResult.getBody());

 }

 // 修改

 @Test
 public void testUpdateItem() throws Exception {
  // http://manager.aaaaaa.com/rest/item/interface/{id}

  String url = "http://manager.aaaaaa.com/rest/item/interface";

  Map<String, Object> map = new HashMap<String, Object>();
  // title=測試RESTful風格的接口&price=1000&num=1&cid=888&status=1
  map.put("title", "測試APIService調用修改接口");
  map.put("id", "44");

  HttpResult httpResult = this.apiService.doPut(url, map);

  System.out.println(httpResult.getCode());
  System.out.println(httpResult.getBody());

 }

 // 刪除
 @Test
 public void testDeleteItemById() throws Exception {
  // http://manager.aaaaaa.com/rest/item/interface/{id}

  String url = "http://manager.aaaaaa.com/rest/item/interface/44";

  HttpResult httpResult = this.apiService.doDelete(url, null);

  System.out.println(httpResult.getCode());
  System.out.println(httpResult.getBody());

 }

}