一、HttpClient
（一）HttpClient 客户端
1、HttpClient 是 apache 的开源，需要引入两个包：httpclient-4.2.4.jar 和 httpcore-4.2.2.jar。
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/**
* HttpClien 的客户端访问
*/
private
void
httpClientVisit() {
String clientResponse =
""
;
try
{
HttpClient client =
new
DefaultHttpClient();
HttpPost request =
new
HttpPost(mUrl);
//不是表单数据提交，这边使用 StringEntity 即可
//UrlEncodedFormEntity等都是 HttpEntity 接口的实现类
StringEntity entity =
new
StringEntity(mRequestXml,
"UTF-8"
);
//编码
entity.setContentType(
"text/xml"
);
request.setEntity(entity);
// 发送请求
HttpResponse response = client.execute(request);
org.apache.http.HttpEntity httpEntity = response.getEntity();
if
(httpEntity !=
null
) {
// EntityUtils.toString 如果不指定编码，EntityUtils默认会使用ISO_8859_1进行编码
clientResponse = EntityUtils.toString(httpEntity,
"UTF-8"
);
// 记得设置编码或者如下
// 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();
}
}
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（二）HttpClient 详解
1、Post方式访问
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/**
* post方式提交表单（模拟用户登录请求）
*/
public
void
postForm() {
String url =
"http://localhost:8080/Java_WS_Server/rest/surpolicy/sendXml"
;
// 创建默认的httpClient实例.
HttpClient client =
new
DefaultHttpClient();
// 创建httppost
HttpPost httppost =
new
HttpPost(url);
// 创建参数队列
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"
);
//编码
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"
));
//编码
System.out.println(
"--------------------------------------"
);
}
}
finally
{
}
}
catch
(ClientProtocolException e) {
e.printStackTrace();
}
catch
(UnsupportedEncodingException e1) {
e1.printStackTrace();
}
catch
(IOException e) {
e.printStackTrace();
}
finally
{
}
}
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2、Get方式访问
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/**
* 发送 get请求
*/
public
void
get() {
try
{
HttpClient client =
new
DefaultHttpClient();
// 创建httpget.
HttpGet httpget =
new
HttpGet(
"http://www.baidu.com/"
);
System.out.println(
"executing request "
+ httpget.getURI());
// 执行get请求.
HttpResponse response = client.execute(httpget);
try
{
// 获取响应实体
HttpEntity entity = response.getEntity();
System.out.println(
"--------------------------------------"
);
// 打印响应状态
System.out.println(response.getStatusLine());
if
(entity !=
null
) {
// 打印响应内容长度
System.out.println(
"Response content length: "
+ entity.getContentLength());
// 打印响应内容
System.out.println(
"Response content: "
+ EntityUtils.toString(entity));
}
System.out.println(
"------------------------------------"
);
}
finally
{
}
}
catch
(ClientProtocolException e) {
e.printStackTrace();
}
catch
(IOException e) {
e.printStackTrace();
}
finally
{}
}
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3、乱码问题：
1）利用：UrlEncodedFormEntity等 entity 容器，实现发送内容的编码：
UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); //编码
StringEntity entity = new StringEntity(mRequestXml, "UTF-8");//编码
2、EntityUtils.toString()方法的转码，实现返回内容的编码：
EntityUtils.toString 如果不指定编码，EntityUtils默认会使用ISO_8859_1进行编码
clientResponse = EntityUtils.toString(httpEntity, "UTF-8");// 记得设置编码或者如下
clientResponse = new String(EntityUtils.toString(httpEntity).getBytes("ISO_8859_1"), "UTF-8");
二、RestTemplate
（一）RestTemplate 客户端
1、RestTemplate 是Spring的封装，需要spring的包 spring-web-3.0.7.RELEASE.jar
2、客户端代码：
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/**
* RestTemplate 客户端访问
*/
private
void
RestTemplateVisit() {
String returnXml =
""
;
// 核心返回结果报文字符串
try
{
//复杂构造函数的使用
SimpleClientHttpRequestFactory requestFactory =
new
SimpleClientHttpRequestFactory();
requestFactory.setConnectTimeout(
1000
);
// 设置超时
requestFactory.setReadTimeout(
1000
);
//利用复杂构造器可以实现超时设置，内部实际实现为 HttpClient
RestTemplate restTemplate =
new
RestTemplate(requestFactory);
//设置HTTP请求头信息，实现编码等
HttpHeaders requestHeaders =
new
HttpHeaders();
// requestHeaders.set("Accept", "text/");
requestHeaders.set(
"Accept-Charset"
,
"utf-8"
);
requestHeaders.set(
"Content-type"
,
"text/xml; charset=utf-8"
);
// 设置编码
//利用容器实现数据封装，发送
HttpEntity<String> entity =
new
HttpEntity<String>(mRequestXml, requestHeaders);
returnXml = restTemplate.postForObject(mUrl, entity, String.
class
);
// 转码原因：RestTemplate默认是使用org.springframework.http.converter.StringHttpMessageConverter来解析
// StringHttpMessageConverter 默认用的 ISO-8859-1来编码的
returnXml =
new
String(returnXml.getBytes(
"ISO-8859-1"
),
"utf-8"
);
}
catch
(UnsupportedEncodingException e) {
e.printStackTrace();
}
System.out.println(
"restTemplate客户端访问返回： \n"
+ returnXml);
}
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具体的参考这个博客：
http://blog.csdn.net/u012228718/article/details/42028951
https://www.cnblogs.com/fengli9998/p/8028250.html