使用HttpClient调用接口的实例讲解

一，编写返回对象

public class HttpResult {
// 响应的状态码
private int code;

// 响应的响应体
private String body;
get/set…
}

二，封装HttpClient

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 创建HttpClinet，相当于打开浏览器
  this.httpClient = HttpClients.createDefault();
 }

 /**
  * 带参数的get请求
  *
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doGet(String url, Map<String, Object> map) throws Exception {

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

  // 判断参数map是否为非空
  if (map != null) {
   // 遍历参数
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    // 设置参数
    uriBuilder.setParameter(entry.getKey(), entry.getValue().toString());
   }
  }

  // 2 创建httpGet对象，相当于设置url请求地址
  HttpGet httpGet = new HttpGet(uriBuilder.build());

  // 3 使用HttpClient执行httpGet，相当于按回车，发起请求
  CloseableHttpResponse response = this.httpClient.execute(httpGet);

  // 4 解析结果，封装返回对象httpResult，相当于显示相应的结果
  // 状态码
  // response.getStatusLine().getStatusCode();
  // 响应体，字符串，如果response.getEntity()为空，下面这个代码会报错,所以解析之前要做非空的判断
  // EntityUtils.toString(response.getEntity(), "UTF-8");
  HttpResult httpResult = null;
  // 解析数据封装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;
 }

 /**
  * 不带参数的get请求
  *
  * @param url
  * @return
  * @throws Exception
  */
 public HttpResult doGet(String url) throws Exception {
  HttpResult httpResult = this.doGet(url, null);
  return httpResult;
 }

 /**
  * 带参数的post请求
  *
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doPost(String url, Map<String, Object> map) throws Exception {
  // 声明httpPost请求
  HttpPost httpPost = new HttpPost(url);

  // 判断map不为空
  if (map != null) {
   // 声明存放参数的List集合
   List<NameValuePair> params = new ArrayList<NameValuePair>();

   // 遍历map，设置参数到list中
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    params.add(new BasicNameValuePair(entry.getKey(), entry.getValue().toString()));
   }

   // 创建form表单对象
   UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "UTF-8");

   // 把表单对象设置到httpPost中
   httpPost.setEntity(formEntity);
  }

  // 使用HttpClient发起请求，返回response
  CloseableHttpResponse response = this.httpClient.execute(httpPost);

  // 解析response封装返回对象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(), "");
  }

  // 返回结果
  return httpResult;
 }

 /**
  * 不带参数的post请求
  *
  * @param url
  * @return
  * @throws Exception
  */
 public HttpResult doPost(String url) throws Exception {
  HttpResult httpResult = this.doPost(url, null);
  return httpResult;
 }

 /**
  * 带参数的Put请求
  *
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doPut(String url, Map<String, Object> map) throws Exception {
  // 声明httpPost请求
  HttpPut httpPut = new HttpPut(url);

  // 判断map不为空
  if (map != null) {
   // 声明存放参数的List集合
   List<NameValuePair> params = new ArrayList<NameValuePair>();

   // 遍历map，设置参数到list中
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    params.add(new BasicNameValuePair(entry.getKey(), entry.getValue().toString()));
   }

   // 创建form表单对象
   UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "UTF-8");

   // 把表单对象设置到httpPost中
   httpPut.setEntity(formEntity);
  }

  // 使用HttpClient发起请求，返回response
  CloseableHttpResponse response = this.httpClient.execute(httpPut);

  // 解析response封装返回对象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(), "");
  }

  // 返回结果
  return httpResult;
 }

 /**
  * 带参数的Delete请求
  *
  * @param url
  * @param map
  * @return
  * @throws Exception
  */
 public HttpResult doDelete(String url, Map<String, Object> map) throws Exception {

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

  // 判断参数map是否为非空
  if (map != null) {
   // 遍历参数
   for (Map.Entry<String, Object> entry : map.entrySet()) {
    // 设置参数
    uriBuilder.setParameter(entry.getKey(), entry.getValue().toString());
   }
  }

  // 2 创建httpGet对象，相当于设置url请求地址
  HttpDelete httpDelete = new HttpDelete(uriBuilder.build());

  // 3 使用HttpClient执行httpGet，相当于按回车，发起请求
  CloseableHttpResponse response = this.httpClient.execute(httpDelete);

  // 4 解析结果，封装返回对象httpResult，相当于显示相应的结果
  // 状态码
  // response.getStatusLine().getStatusCode();
  // 响应体，字符串，如果response.getEntity()为空，下面这个代码会报错,所以解析之前要做非空的判断
  // EntityUtils.toString(response.getEntity(), "UTF-8");
  HttpResult httpResult = null;
  // 解析数据封装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;
 }

}

三，调用接口

1. package cn.xxxxxx.httpclient.test; 
2.  
3. import java.util.HashMap; 
4. import java.util.Map; 
5.  
6. import org.junit.Before; 
7. import org.junit.Test; 
8.  
9. import cn.itcast.httpclient.APIService; 
10. import cn.itcast.httpclient.HttpResult; 
11.  
12. public class APIServiceTest { 
13.  
14.  private APIService apiService; 
15.  
16.  @Before 
17.  public void init() { 
18.   this.apiService = new APIService(); 
19.  } 
20.  
21.  // 查询 
22.  @Test 
23.  public void testQueryItemById() throws Exception { 
24.   // http://manager.aaaaaa.com/rest/item/interface/{id} 
25.  
26.   String url = "http://manager.aaaaaa.com/rest/item/interface/42"; 
27.  
28.   HttpResult httpResult = this.apiService.doGet(url); 
29.  
30.   System.out.println(httpResult.getCode()); 
31.   System.out.println(httpResult.getBody()); 
32.  
33.  } 
34.  
35.  // 新增 
36.  @Test 
37.  public void testSaveItem() throws Exception { 
38.   // http://manager.aaaaaa.com/rest/item/interface/{id} 
39.  
40.   String url = "http://manager.aaaaaa.com/rest/item/interface"; 
41.  
42.   Map<String, Object> map = new HashMap<String, Object>(); 
43.   // title=测试RESTful风格的接口&price=1000&num=1&cid=888&status=1 
44.   map.put("title", "测试APIService调用新增接口"); 
45.   map.put("price", "1000"); 
46.   map.put("num", "1"); 
47.   map.put("cid", "666"); 
48.   map.put("status", "1"); 
49.  
50.   HttpResult httpResult = this.apiService.doPost(url, map); 
51.  
52.   System.out.println(httpResult.getCode()); 
53.   System.out.println(httpResult.getBody()); 
54.  
55.  } 
56.  
57.  // 修改 
58.  
59.  @Test 
60.  public void testUpdateItem() throws Exception { 
61.   // http://manager.aaaaaa.com/rest/item/interface/{id} 
62.  
63.   String url = "http://manager.aaaaaa.com/rest/item/interface"; 
64.  
65.   Map<String, Object> map = new HashMap<String, Object>(); 
66.   // title=测试RESTful风格的接口&price=1000&num=1&cid=888&status=1 
67.   map.put("title", "测试APIService调用修改接口"); 
68.   map.put("id", "44"); 
69.  
70.   HttpResult httpResult = this.apiService.doPut(url, map); 
71.  
72.   System.out.println(httpResult.getCode()); 
73.   System.out.println(httpResult.getBody()); 
74.  
75.  } 
76.  
77.  // 删除 
78.  @Test 
79.  public void testDeleteItemById() throws Exception { 
80.   // http://manager.aaaaaa.com/rest/item/interface/{id} 
81.  
82.   String url = "http://manager.aaaaaa.com/rest/item/interface/44"; 
83.  
84.   HttpResult httpResult = this.apiService.doDelete(url, null); 
85.  
86.   System.out.println(httpResult.getCode()); 
87.   System.out.println(httpResult.getBody()); 
88.  
89.  } 
90.  
91. } 

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原文链接：http://www.cnblogs.com/javaxiaoxin/archive/2017/10/06/7633017.html