Httpclient與RestTemplate的比較（比httpClient更優雅的Restful URL訪問）
阿新 • • 發佈：2017-12-12
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一、HttpClient
（一）HttpClient 客戶端
1、HttpClient 是 apache 的開源，需要引入兩個包：httpclient-4.2.4.jar 和 httpcore-4.2.2.jar。
/**
* HttpClien 的客戶端訪問
*/
private void httpClientVisit() {
String clientResponse = "";
try {
HttpClient client = new DefaultHttpClient();
HttpPost request = new HttpPost(mUrl);
//不是表單數據提交，這邊使用 StringEntity 即可
//UrlEncodedFormEntity等都是 HttpEntity 接口的實現類
StringEntity entity = new StringEntity(mRequestXml, "UTF-8");//編碼
entity.setContentType("text/xml");
request.setEntity(entity);
// 發送請求
HttpResponse response = client.execute(request);
org.apache.http.HttpEntity httpEntity = response.getEntity();
if (httpEntity != null) {
// EntityUtils.toString 如果不指定編碼，EntityUtils默認會使用ISO_8859_1進行編碼
clientResponse = EntityUtils.toString(httpEntity, "UTF-8");// 記得設置編碼或者如下
// clientResponse = new String(EntityUtils.toString(httpEntity).getBytes("ISO_8859_1"), "UTF-8");
}
if (clientResponse == null || "".equals(clientResponse)) {
System.err.println("clientResponse is null or empty.");
}
System.out.println(clientResponse);
} catch (Exception e) {
e.printStackTrace();
}
}
（二）HttpClient 詳解
1、Post方式訪問
/**
* post方式提交表單（模擬用戶登錄請求）
*/
public void postForm() {
String url = "http://localhost:8080/Java_WS_Server/rest/surpolicy/sendXml";
// 創建默認的httpClient實例.
HttpClient client = new DefaultHttpClient();
// 創建httppost
HttpPost httppost = new HttpPost(url);
// 創建參數隊列
List<NameValuePair> formparams = new ArrayList<NameValuePair>();
formparams.add(new BasicNameValuePair("username", "admin"));
formparams.add(new BasicNameValuePair("password", "123456"));
UrlEncodedFormEntity uefEntity;
try {
uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); //編碼
httppost.setEntity(uefEntity);
System.out.println("executing request " + httppost.getURI());
HttpResponse response = client.execute(httppost);
Header[] headers = response.getAllHeaders();
for(int i=0; i<headers.length; i++){
System.out.println(headers[i].getName());
}
try {
HttpEntity entity = response.getEntity();
if (entity != null) {
System.out.println("--------------------------------------");
System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8")); //編碼
System.out.println("--------------------------------------");
}
} finally {
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
}
}
2、Get方式訪問
/**
* 發送 get請求
*/
public void get() {
try {
HttpClient client = new DefaultHttpClient();
// 創建httpget.
HttpGet httpget = new HttpGet("http://www.baidu.com/");
System.out.println("executing request " + httpget.getURI());
// 執行get請求.
HttpResponse response = client.execute(httpget);
try {
// 獲取響應實體
HttpEntity entity = response.getEntity();
System.out.println("--------------------------------------");
// 打印響應狀態
System.out.println(response.getStatusLine());
if (entity != null) {
// 打印響應內容長度
System.out.println("Response content length: " + entity.getContentLength());
// 打印響應內容
System.out.println("Response content: " + EntityUtils.toString(entity));
}
System.out.println("------------------------------------");
} finally {
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {}
}
3、亂碼問題：
1）利用：UrlEncodedFormEntity等 entity 容器，實現發送內容的編碼：
UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); //編碼
StringEntity entity = new StringEntity(mRequestXml, "UTF-8");//編碼
2、EntityUtils.toString()方法的轉碼，實現返回內容的編碼：
EntityUtils.toString 如果不指定編碼，EntityUtils默認會使用ISO_8859_1進行編碼
clientResponse = EntityUtils.toString(httpEntity, "UTF-8");// 記得設置編碼或者如下
clientResponse = new String(EntityUtils.toString(httpEntity).getBytes("ISO_8859_1"), "UTF-8");
二、RestTemplate
（一）RestTemplate 客戶端
1、RestTemplate 是Spring的封裝，需要spring的包 spring-web-3.0.7.RELEASE.jar
2、客戶端代碼：
/**
* RestTemplate 客戶端訪問
*/
private void RestTemplateVisit() {
String returnXml = ""; // 核心返回結果報文字符串
try {
//復雜構造函數的使用
SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
requestFactory.setConnectTimeout(1000);// 設置超時
requestFactory.setReadTimeout(1000);
//利用復雜構造器可以實現超時設置，內部實際實現為 HttpClient
RestTemplate restTemplate = new RestTemplate(requestFactory);
//設置HTTP請求頭信息，實現編碼等
HttpHeaders requestHeaders = new HttpHeaders();
// requestHeaders.set("Accept", "text/");
requestHeaders.set("Accept-Charset", "utf-8");
requestHeaders.set("Content-type", "text/xml; charset=utf-8");// 設置編碼
//利用容器實現數據封裝，發送
HttpEntity<String> entity = new HttpEntity<String>(mRequestXml, requestHeaders);
returnXml = restTemplate.postForObject(mUrl, entity, String.class);
// 轉碼原因：RestTemplate默認是使用org.springframework.http.converter.StringHttpMessageConverter來解析
// StringHttpMessageConverter 默認用的 ISO-8859-1來編碼的
returnXml = new String(returnXml.getBytes("ISO-8859-1"), "utf-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
System.out.println("restTemplate客戶端訪問返回： \n" + returnXml);
}
具體的參考這個博客：
http://blog.csdn.net/u012228718/article/details/42028951
Httpclient與RestTemplate的比較（比httpClient更優雅的Restful URL訪問）