HTTPClient和HttpURLConnection实例对比

HttpURLConnection是java的标准类，什么都没封装。

HTTPClient是个开源框架，封装了访问http的请求头，参数，内容体，响应等等。

简单来说，HTTPClient就是一个增强版的HttpURLConnection，HttpURLConnection可以做的事情HTTPClient全部可以做；HttpURLConnection没有提供的有些功能，HTTPClient也提供了，但它只是关注于如何发送请求、接收响应，以及管理HTTP连接。

实例：

package com.cn.common.controller;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.httpclient.HttpClient;import org.apache.commons.httpclient.HttpStatus;import org.apache.commons.httpclient.methods.PostMethod;import org.apache.commons.httpclient.params.HttpMethodParams;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;@Controller@RequestMapping("/http")public class HttpClientAndURLConnectionController {@RequestMapping("/testHttp")public void testHttp(HttpServletRequest req,HttpServletResponse resp) {try {long s1 = System.currentTimeMillis();testHttpClient();long s2 = System.currentTimeMillis();testHttpURlConnection();long s3 = System.currentTimeMillis();System.out.println((s2-s1)+" "+(s3-s2));} catch (IOException e) {e.printStackTrace();}}public void testHttpClient() throws IOException{System.out.println("testHttpClient");//请求方法    String result="";    String url = "http://192.168.2.111:8088/era/user/getUserById";    HttpClient client =new HttpClient();    //设置连接时间    client.getHttpConnectionManager().getParams().setConnectionTimeout(30000);    //解决乱码问题    client.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET,"UTF-8");    PostMethod method =new PostMethod(url);    //传参    method.addParameter("userId", "100");    int status = client.executeMethod(method);    if(status == HttpStatus.SC_OK){    result = method.getResponseBodyAsString();    }    System.out.println(result);    method.releaseConnection();    }public void testHttpURlConnection() throws IOException{System.out.println("testHttpURlConnection");        String result = "";        URL url = new URL("http://192.168.2.111:8088/era/user/getUserById");        HttpURLConnection conn = (HttpURLConnection) url.openConnection();        conn.setConnectTimeout(30000);//设置连接主机超时（单位：毫秒）        conn.setReadTimeout(30000);//设置从主机读取数据超时（单位：毫秒）        conn.setRequestMethod("POST");//设定请求的方法为"POST"，默认是GET        conn.setDoInput(true);//设置是否从httpUrlConnection读入，默认情况下是true        conn.setDoOutput(true);//设置是否向httpUrlConnection输出，因为这个是post请求，参数要放在http正文内，因此需要设为true, 默认情况下是false        conn.setUseCaches(false);//Post请求不能使用缓存        conn.setInstanceFollowRedirects(false);        conn.setRequestProperty("Content-Type", "text/html; charset=utf-8");        conn.connect();        int responsecode = conn.getResponseCode();        if(responsecode == HttpURLConnection.HTTP_OK){ //对应HTTP响应中状态行的响应码        //操作请求流，这里对应HTTP响应中的响应正文         InputStream urlStream = conn.getInputStream();            BufferedReader reader = new BufferedReader(new InputStreamReader(urlStream,"utf-8"));            String s = "";            while ((s = reader.readLine()) != null) {                result += s;            }            reader.close();            urlStream.close();        }        System.out.println(result);        if(conn != null){        conn.disconnect();        }    }}

调用的url方法：

@RequestMapping("/getUserById")public void getUserById(HttpServletRequest req,HttpServletResponse resp) throws IOException{    resp.setContentType("text/html;charset=utf-8");    resp.setCharacterEncoding("UTF-8");    int userId;    if(null == req.getParameter("userId")){    userId = 100;    }else{    userId = Integer.parseInt(req.getParameter("userId"));    }    User user = this.userService.selectByPrimaryKey(userId);    ObjectMapper mapper = new ObjectMapper();    String result = mapper.writeValueAsString(user);    resp.getWriter().print(result);}

项目启动后，第一次执行testHttp方法后控制台信息：

testHttpClient2016-07-31 00:24:46,513 DEBUG [org.apache.commons.httpclient.HttpClient] - Java version: 1.7.0_752016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Java vendor: Oracle Corporation2016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Java class path: D:\apache-tomcat-8.0.33/bin/bootstrap.jar;D:\apache-tomcat-8.0.33/bin/tomcat-juli.jar;D:\Program Files\Java\jdk1.7.0_75/lib/tools.jar2016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Operating system name: Windows 8.12016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Operating system architecture: amd642016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Operating system version: 6.32016-07-31 00:24:46,516 DEBUG [org.apache.commons.httpclient.HttpClient] - SUN 1.7: SUN (DSA key/parameter generation; DSA signing; SHA-1, MD5 digests; SecureRandom; X.509 certificates; JKS keystore; PKIX CertPathValidator; PKIX CertPathBuilder; LDAP, Collection CertStores, JavaPolicy Policy; JavaLoginConfig Configuration)2016-07-31 00:24:46,517 DEBUG [org.apache.commons.httpclient.HttpClient] - SunRsaSign 1.7: Sun RSA signature provider2016-07-31 00:24:46,517 DEBUG [org.apache.commons.httpclient.HttpClient] - SunEC 1.7: Sun Elliptic Curve provider (EC, ECDSA, ECDH)2016-07-31 00:24:46,517 DEBUG [org.apache.commons.httpclient.HttpClient] - SunJSSE 1.7: Sun JSSE provider(PKCS12, SunX509 key/trust factories, SSLv3, TLSv1)2016-07-31 00:24:46,517 DEBUG [org.apache.commons.httpclient.HttpClient] - SunJCE 1.7: SunJCE Provider (implements RSA, DES, Triple DES, AES, Blowfish, ARCFOUR, RC2, PBE, Diffie-Hellman, HMAC)2016-07-31 00:24:46,517 DEBUG [org.apache.commons.httpclient.HttpClient] - SunJGSS 1.7: Sun (Kerberos v5, SPNEGO)2016-07-31 00:24:46,517 DEBUG [org.apache.commons.httpclient.HttpClient] - SunSASL 1.7: Sun SASL provider(implements client mechanisms for: DIGEST-MD5, GSSAPI, EXTERNAL, PLAIN, CRAM-MD5, NTLM; server mechanisms for: DIGEST-MD5, GSSAPI, CRAM-MD5, NTLM)2016-07-31 00:24:46,518 DEBUG [org.apache.commons.httpclient.HttpClient] - XMLDSig 1.0: XMLDSig (DOM XMLSignatureFactory; DOM KeyInfoFactory)2016-07-31 00:24:46,518 DEBUG [org.apache.commons.httpclient.HttpClient] - SunPCSC 1.7: Sun PC/SC provider2016-07-31 00:24:46,518 DEBUG [org.apache.commons.httpclient.HttpClient] - SunMSCAPI 1.7: Sun's Microsoft Crypto API provider2016-07-31 00:24:46,535 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.useragent = Jakarta Commons-HttpClient/3.12016-07-31 00:24:46,549 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.version = HTTP/1.12016-07-31 00:24:46,556 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.connection-manager.class = class org.apache.commons.httpclient.SimpleHttpConnectionManager2016-07-31 00:24:46,556 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.cookie-policy = default2016-07-31 00:24:46,557 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.element-charset = US-ASCII2016-07-31 00:24:46,557 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.content-charset = ISO-8859-12016-07-31 00:24:46,562 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.method.retry-handler = org.apache.commons.httpclient.DefaultHttpMethodRetryHandler@a9d54382016-07-31 00:24:46,563 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.dateparser.patterns = [EEE, dd MMM yyyy HH:mm:ss zzz, EEEE, dd-MMM-yy HH:mm:ss zzz, EEE MMM d HH:mm:ss yyyy, EEE, dd-MMM-yyyy HH:mm:ss z, EEE, dd-MMM-yyyy HH-mm-ss z, EEE, dd MMM yy HH:mm:ss z, EEE dd-MMM-yyyy HH:mm:ss z, EEE dd MMM yyyy HH:mm:ss z, EEE dd-MMM-yyyy HH-mm-ss z, EEE dd-MMM-yy HH:mm:ss z, EEE dd MMM yy HH:mm:ss z, EEE,dd-MMM-yy HH:mm:ss z, EEE,dd-MMM-yyyy HH:mm:ss z, EEE, dd-MM-yyyy HH:mm:ss z]2016-07-31 00:24:46,588 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.connection.timeout = 300002016-07-31 00:24:46,588 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.content-charset = UTF-82016-07-31 00:24:46,727 DEBUG [org.apache.commons.httpclient.HttpConnection] - Open connection to 192.168.2.111:80882016-07-31 00:24:46,744 DEBUG [httpclient.wire.header] - >> "POST /era/user/getUserById HTTP/1.1[\r][\n]"2016-07-31 00:24:46,747 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Adding Host request header2016-07-31 00:24:46,871 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-82016-07-31 00:24:46,900 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-82016-07-31 00:24:46,902 DEBUG [httpclient.wire.header] - >> "User-Agent: Jakarta Commons-HttpClient/3.1[\r][\n]"2016-07-31 00:24:46,903 DEBUG [httpclient.wire.header] - >> "Host: 192.168.2.111:8088[\r][\n]"2016-07-31 00:24:46,903 DEBUG [httpclient.wire.header] - >> "Content-Length: 10[\r][\n]"2016-07-31 00:24:46,903 DEBUG [httpclient.wire.header] - >> "Content-Type: application/x-www-form-urlencoded[\r][\n]"2016-07-31 00:24:46,907 DEBUG [httpclient.wire.header] - >> "[\r][\n]"2016-07-31 00:24:46,911 DEBUG [httpclient.wire.content] - >> "userId=100"2016-07-31 00:24:46,913 DEBUG [org.apache.commons.httpclient.methods.EntityEnclosingMethod] - Request body sent2016-07-31 00:24:47,041 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession2016-07-31 00:24:47,074 DEBUG [org.mybatis.spring.SqlSessionUtils] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@631e7edd] was not registered for synchronization because synchronization is not active2016-07-31 00:24:47,168 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring2016-07-31 00:24:47,197 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==>  Preparing: select id, user_name, password, age from user where id = ? 2016-07-31 00:24:47,756 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==> Parameters: 100(Integer)2016-07-31 00:24:47,848 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - <==      Total: 12016-07-31 00:24:47,852 DEBUG [com.alibaba.druid.pool.PreparedStatementPool] - {conn-10001, pstmt-20000} enter cache2016-07-31 00:24:47,854 DEBUG [org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@631e7edd]2016-07-31 00:24:48,085 DEBUG [httpclient.wire.header] - << "HTTP/1.1 200 OK[\r][\n]"2016-07-31 00:24:48,086 DEBUG [httpclient.wire.header] - << "HTTP/1.1 200 OK[\r][\n]"2016-07-31 00:24:48,089 DEBUG [httpclient.wire.header] - << "Server: Apache-Coyote/1.1[\r][\n]"2016-07-31 00:24:48,090 DEBUG [httpclient.wire.header] - << "Content-Type: text/html;charset=UTF-8[\r][\n]"2016-07-31 00:24:48,090 DEBUG [httpclient.wire.header] - << "Content-Length: 67[\r][\n]"2016-07-31 00:24:48,090 DEBUG [httpclient.wire.header] - << "Date: Sat, 30 Jul 2016 16:24:48 GMT[\r][\n]"2016-07-31 00:24:48,091 DEBUG [httpclient.wire.header] - << "[\r][\n]"2016-07-31 00:24:48,095 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Buffering response body2016-07-31 00:24:48,095 DEBUG [httpclient.wire.content] - << "{"id":100,"userName":"admin[0xe7][0xae][0xa1][0xe7][0x90][0x86][0xe5][0x91][0x98]","password":"123456","age":25}"2016-07-31 00:24:48,097 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Resorting to protocol version default close connection policy2016-07-31 00:24:48,097 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Should NOT close connection, using HTTP/1.12016-07-31 00:24:48,098 DEBUG [org.apache.commons.httpclient.HttpConnection] - Releasing connection back to connection manager.{"id":100,"userName":"admin管理员","password":"123456","age":25}testHttpURlConnection2016-07-31 00:24:48,127 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession2016-07-31 00:24:48,129 DEBUG [org.mybatis.spring.SqlSessionUtils] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1ee42c08] was not registered for synchronization because synchronization is not active2016-07-31 00:24:48,129 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring2016-07-31 00:24:48,130 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==>  Preparing: select id, user_name, password, age from user where id = ? 2016-07-31 00:24:48,131 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==> Parameters: 100(Integer)2016-07-31 00:24:48,137 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - <==      Total: 12016-07-31 00:24:48,138 DEBUG [org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1ee42c08]{"id":100,"userName":"admin管理员","password":"123456","age":25}1598 58

第一次执行后：

  testHttpClient()用时：1598

  testHttpURlConnection()用时：58

第二次执行testHttp方法后控制台信息：

testHttpClient2016-07-31 00:28:09,582 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.connection.timeout = 300002016-07-31 00:28:09,582 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.content-charset = UTF-82016-07-31 00:28:09,583 DEBUG [org.apache.commons.httpclient.HttpConnection] - Open connection to 192.168.2.111:80882016-07-31 00:28:09,586 DEBUG [httpclient.wire.header] - >> "POST /era/user/getUserById HTTP/1.1[\r][\n]"2016-07-31 00:28:09,587 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Adding Host request header2016-07-31 00:28:09,587 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-82016-07-31 00:28:09,590 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-82016-07-31 00:28:09,591 DEBUG [httpclient.wire.header] - >> "User-Agent: Jakarta Commons-HttpClient/3.1[\r][\n]"2016-07-31 00:28:09,592 DEBUG [httpclient.wire.header] - >> "Host: 192.168.2.111:8088[\r][\n]"2016-07-31 00:28:09,592 DEBUG [httpclient.wire.header] - >> "Content-Length: 10[\r][\n]"2016-07-31 00:28:09,593 DEBUG [httpclient.wire.header] - >> "Content-Type: application/x-www-form-urlencoded[\r][\n]"2016-07-31 00:28:09,593 DEBUG [httpclient.wire.header] - >> "[\r][\n]"2016-07-31 00:28:09,593 DEBUG [httpclient.wire.content] - >> "userId=100"2016-07-31 00:28:09,594 DEBUG [org.apache.commons.httpclient.methods.EntityEnclosingMethod] - Request body sent2016-07-31 00:28:09,601 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession2016-07-31 00:28:09,602 DEBUG [org.mybatis.spring.SqlSessionUtils] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@240543cf] was not registered for synchronization because synchronization is not active2016-07-31 00:28:09,603 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring2016-07-31 00:28:09,605 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==>  Preparing: select id, user_name, password, age from user where id = ? 2016-07-31 00:28:09,606 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==> Parameters: 100(Integer)2016-07-31 00:28:09,611 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - <==      Total: 12016-07-31 00:28:09,612 DEBUG [org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@240543cf]2016-07-31 00:28:09,616 DEBUG [httpclient.wire.header] - << "HTTP/1.1 200 OK[\r][\n]"2016-07-31 00:28:09,617 DEBUG [httpclient.wire.header] - << "HTTP/1.1 200 OK[\r][\n]"2016-07-31 00:28:09,617 DEBUG [httpclient.wire.header] - << "Server: Apache-Coyote/1.1[\r][\n]"2016-07-31 00:28:09,617 DEBUG [httpclient.wire.header] - << "Content-Type: text/html;charset=UTF-8[\r][\n]"2016-07-31 00:28:09,618 DEBUG [httpclient.wire.header] - << "Content-Length: 67[\r][\n]"2016-07-31 00:28:09,618 DEBUG [httpclient.wire.header] - << "Date: Sat, 30 Jul 2016 16:28:09 GMT[\r][\n]"2016-07-31 00:28:09,618 DEBUG [httpclient.wire.header] - << "[\r][\n]"2016-07-31 00:28:09,618 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Buffering response body2016-07-31 00:28:09,619 DEBUG [httpclient.wire.content] - << "{"id":100,"userName":"admin[0xe7][0xae][0xa1][0xe7][0x90][0x86][0xe5][0x91][0x98]","password":"123456","age":25}"2016-07-31 00:28:09,619 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Resorting to protocol version default close connection policy2016-07-31 00:28:09,619 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Should NOT close connection, using HTTP/1.12016-07-31 00:28:09,620 DEBUG [org.apache.commons.httpclient.HttpConnection] - Releasing connection back to connection manager.{"id":100,"userName":"admin管理员","password":"123456","age":25}testHttpURlConnection2016-07-31 00:28:09,629 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession2016-07-31 00:28:09,630 DEBUG [org.mybatis.spring.SqlSessionUtils] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4636317d] was not registered for synchronization because synchronization is not active2016-07-31 00:28:09,631 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring2016-07-31 00:28:09,631 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==>  Preparing: select id, user_name, password, age from user where id = ? 2016-07-31 00:28:09,632 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - ==> Parameters: 100(Integer)2016-07-31 00:28:09,637 DEBUG [com.cn.eagle.dao.UserMapper.selectByPrimaryKey] - <==      Total: 12016-07-31 00:28:09,640 DEBUG [org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4636317d]{"id":100,"userName":"admin管理员","password":"123456","age":25}39 25

第二次执行后：

  testHttpClient()用时：39

  testHttpURlConnection()用时：25

总的来说，在大压力或者连续不断发请求的情况下，HttpClient不会比HttpURLConnection慢多少，因为保持了底层的Socket连接，不用每次都重新连接。