import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.URIException;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.commons.httpclient.util.URIUtil;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* HTTP工具箱
*
* @author leizhimin 2009-6-19 16:36:18
*/
public final class HttpTookit {
private static Log log = LogFactory.getLog(HttpTookit.class);
/**
* 执行一个HTTP GET请求，返回请求响应的HTML
*
* @param url 请求的URL地址
* @param queryString 请求的查询参数,可以为null
* @return 返回请求响应的HTML
*/
public static String doGet(String url, String queryString) {
String response = null;
HttpClient client = new HttpClient();
HttpMethod method = new GetMethod(url);
try {
if (StringUtils.isNotBlank(queryString))
method.setQueryString(URIUtil.encodeQuery(queryString));
client.executeMethod(method);
if (method.getStatusCode() == HttpStatus.SC_OK) {
response = method.getResponseBodyAsString();
}
} catch (URIException e) {
log.error("执行HTTP Get请求时，编码查询字符串“" + queryString + "”发生异常！", e);
} catch (IOException e) {
log.error("执行HTTP Get请求" + url + "时，发生异常！", e);
} finally {
method.releaseConnection();
}
return response;
}
/**
* 执行一个HTTP POST请求，返回请求响应的HTML
*
* @param url 请求的URL地址
* @param params 请求的查询参数,可以为null
* @return 返回请求响应的HTML
*/
public static String doPost(String url, Map params) {
String response = null;
HttpClient client = new HttpClient();
HttpMethod method = new PostMethod(url);
for (Iterator it = params.entrySet().iterator(); it.hasNext();) {
}
//设置Http Post数据
if (params != null) {
HttpMethodParams p = new HttpMethodParams();
for (Map.Entry entry : params.entrySet()) {
p.setParameter(entry.getKey(), entry.getValue());
}
method.setParams(p);
}
try {
client.executeMethod(method);
if (method.getStatusCode() == HttpStatus.SC_OK) {
response = method.getResponseBodyAsString();
}
} catch (IOException e) {
log.error("执行HTTP Post请求" + url + "时，发生异常！", e);
} finally {
method.releaseConnection();
}
return response;
}
public static void main(String[] args) {
String x = doPost("http://lavasoft.blog.51cto.com/62575/64994", new HashMap());
System.out.println(x);
}
}
一般网络会给我们提供许多数据接口，我们的一些信息并不是我们本系统提供而是第三方给我们提供的，他们通常会给我们一个提供数据源的接口，访问这个接口可以获取相应的数据用于我们自己的应用中(WebService和现如今的json/xml通过http信息的传输模式都是如此)。
httpClient是一款优秀的基于https协议的网络发送http请求并获取相应的api，下面就来探讨一下如何使用httpClient进行get和post两种方式的http通信。
我们接下来要做的，就是提供一个数据接口，此数据接口提供整数计算服务，传入两个参数(要求是整数)和一个运算符参数，就可以得到最终的运算结果。如，传递param1=1,param2=2,operator='+'，那么接口就会返回result:3。
开发环境:MyEclipse8.5,JDK1.7,Tomcat6.0 httpClient3.0
下面我们开始编写这个Servlet，具体实现就是获取请求中的三个参数(两个运算值一个运算符号)，然后进行计算然后返回结果 (网页直接调用和后台使用 httpclient测试)：
package httpcall;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class TestHTTPServer extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("gbk");
PrintWriter out=response.getWriter();
String param1=request.getParameter("param1");
out.println("param1="+param1);
String param2=request.getParameter("param2");
out.println("param2="+param2);
String operator=request.getParameter("operator");
out.println(operator.equals(" ")?"operator=+":"operator="+operator);
if(param1 == null || param1.equals("") || param1.length()<=0){
out.println("http call failed,参数param1不能为空，程序退出");
}else if(param2 == null || param2.equals("") || param2.length()<=0){
out.println("http call failed,参数param2不能为空，程序退出");
}else if(operator == null || operator.equals("") || operator.length()<=0){
out.println("http call failed,参数operator不能为空，程序退出");
}else{
out.println("---http call success---");
}
int n=Integer.parseInt(param1);
int m=Integer.parseInt(param2);
if(operator.equals(" ")){
out.println("result:"+(n+m));
}else if(operator.equals("-")){
out.println("result:"+(n-m));
}else if(operator.equals("*")){
out.println("result:"+(n*m));
}else if(operator.equals("/")){
out.println("result:"+(n/m));
}else{
out.println("---unknow error---");
}
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
注意:“+”号通过URL传递到后台会被默认转义为空格“ ”，所以这里验证“+”号是用的是空格。
将Servlet部署到web服务器中（略）
此时，在浏览器访问我们的服务，参数分别输入6、2和*，得到最终结果是6乘以2为12：
其他方法测试（略）
好，我们的服务接口已经提供完毕了，接下来我们使用httpClient的get和post对这个http接口进行调用。
我们使用httpClinet分别编写了使用get与post方式进行http数据传输的方法，在main主方法中，对其进行了测试，分别使用get和post请求获取数据接口服务计算的结果：
package httpcall;
import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class HttpClientUtil {
private static final Log log=LogFactory.getLog(HttpClientUtil.class);
/**
* get 方式
* @param param1
* @param param2
* @param opt
* @return String
* */
public static String getHttp(String param1,String param2,String opt){
String responseMsg="";
//1.构造HttpClient的实例
HttpClient httpClient=new HttpClient();
//用于测试的http接口的url
String url="http://localhost:8081/HttpTest/httpServer?param1="
+param1+"¶m2="+param2+"&operator="+opt;
//2.创建GetMethod的实例
GetMethod getMethod=new GetMethod(url);
//使用系统的默认的恢复策略
getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
new DefaultHttpMethodRetryHandler());
try {
//3.执行getMethod，调用http接口
httpClient.executeMethod(getMethod);
//4.读取内容
byte[] responseBody=getMethod.getResponseBody();
//5.处理返回的内容
responseMsg=new String(responseBody);
log.info(responseMsg);
} catch (Exception e) {
e.printStackTrace();
}finally{
//6.释放连接
getMethod.releaseConnection();
}
return responseMsg;
}
/**
* post 方式
* @param param1
* @param param2
* @param opt
* @return String
* */
public static String postHttp(String param1,String param2,String opt){
String responseMsg="";
//1.构造HttpClient的实例
HttpClient httpClient=new HttpClient();
httpClient.getParams().setContentCharset("GBK");
String url="http://localhost:8081/HttpTest/httpServer";
//2.构造PostMethodd的实例
PostMethod postMethod=new PostMethod(url);
//3.把参数值放入到PostMethod对象中
postMethod.addParameter("param1",param1);
postMethod.addParameter("param2",param2);
postMethod.addParameter("operator",opt);
try {
//4.执行postMethod，调用http接口
httpClient.executeMethod(postMethod);//200
//5.读取内容
responseMsg=postMethod.getResponseBodyAsString().trim();
//6.处理返回的内容
log.info(responseMsg);
} catch (Exception e) {
e.printStackTrace();
}finally{
//7.释放连接
postMethod.releaseConnection();
}
return responseMsg;
}
/**
* 测试的main方法
* @param args
* */
public static void main(String[] args) {
String param1="6";
String param2="2";
String opt="*";
System.out.println("get方式调用http接口\n"+getHttp(param1,param2,opt));
System.out.println("post方式调用http接口\n"+postHttp(param1,param2,opt));
}
}
运行结果：
证明我们成功使用httpClient访问了第三方数据接口，并获取了相应的数据。
http://blog.csdn.net/acmman/article/details/51839367
其他参考资料
Java模拟HTTP的Get和Post请求
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.URIException;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.commons.httpclient.util.URIUtil;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* HTTP工具箱
*
* @author leizhimin 2009-6-19 16:36:18
*/
public final class HttpTookit {
private static Log log = LogFactory.getLog(HttpTookit.class);
/**
* 执行一个HTTP GET请求，返回请求响应的HTML
*
* @param url 请求的URL地址
* @param queryString 请求的查询参数,可以为null
* @return 返回请求响应的HTML
*/
public static String doGet(String url, String queryString) {
String response = null;
HttpClient client = new HttpClient();
HttpMethod method = new GetMethod(url);
try {
if (StringUtils.isNotBlank(queryString))
method.setQueryString(URIUtil.encodeQuery(queryString));
client.executeMethod(method);
if (method.getStatusCode() == HttpStatus.SC_OK) {
response = method.getResponseBodyAsString();
}
} catch (URIException e) {
log.error("执行HTTP Get请求时，编码查询字符串“" + queryString + "”发生异常！", e);
} catch (IOException e) {
log.error("执行HTTP Get请求" + url + "时，发生异常！", e);
} finally {
method.releaseConnection();
}
return response;
}
/**
* 执行一个HTTP POST请求，返回请求响应的HTML
*
* @param url 请求的URL地址
* @param params 请求的查询参数,可以为null
* @return 返回请求响应的HTML
*/
public static String doPost(String url, Map params) {
String response = null;
HttpClient client = new HttpClient();
HttpMethod method = new PostMethod(url);
for (Iterator it = params.entrySet().iterator(); it.hasNext();) {
}
//设置Http Post数据
if (params != null) {
HttpMethodParams p = new HttpMethodParams();
for (Map.Entry entry : params.entrySet()) {
p.setParameter(entry.getKey(), entry.getValue());
}
method.setParams(p);
}
try {
client.executeMethod(method);
if (method.getStatusCode() == HttpStatus.SC_OK) {
response = method.getResponseBodyAsString();
}
} catch (IOException e) {
log.error("执行HTTP Post请求" + url + "时，发生异常！", e);
} finally {
method.releaseConnection();
}
return response;
}
public static void main(String[] args) {
String x = doPost("http://lavasoft.blog.51cto.com/62575/64994", new HashMap());
System.out.println(x);
}
}
运行后打印结果如下：
Java中使用正则表达式校验字符串 - 熔 岩 - 51CTO技术博客