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：

testHttpClient
2016-07-31 00:24:46,513 DEBUG [org.apache.commons.httpclient.HttpClient] - Java version: 1.7.0_75
2016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Java vendor: Oracle Corporation
2016-07-31 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 FilesJavajdk1.7.0_75/lib/tools.jar
2016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Operating system name: Windows 8.1
2016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Operating system architecture: amd64
2016-07-31 00:24:46,515 DEBUG [org.apache.commons.httpclient.HttpClient] - Operating system version: 6.3
2016-07-31 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 provider
2016-07-31 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 provider
2016-07-31 00:24:46,518 DEBUG [org.apache.commons.httpclient.HttpClient] - SunMSCAPI 1.7: Sun's Microsoft Crypto API provider
2016-07-31 00:24:46,535 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.useragent = Jakarta Commons-HttpClient/3.1
2016-07-31 00:24:46,549 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.version = HTTP/1.1
2016-07-31 00:24:46,556 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.connection-manager.class = class org.apache.commons.httpclient.SimpleHttpConnectionManager
2016-07-31 00:24:46,556 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.cookie-policy = default
2016-07-31 00:24:46,557 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.element-charset = US-ASCII
2016-07-31 00:24:46,557 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.content-charset = ISO-8859-1
2016-07-31 00:24:46,562 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.method.retry-handler = org.apache.commons.httpclient.DefaultHttpMethodRetryHandler@a9d5438
2016-07-31 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 = 30000
2016-07-31 00:24:46,588 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.content-charset = UTF-8
2016-07-31 00:24:46,727 DEBUG [org.apache.commons.httpclient.HttpConnection] - Open connection to 192.168.2.111:8088
2016-07-31 00:24:46,744 DEBUG [httpclient.wire.header] - >> "POST /era/user/getUserById HTTP/1.1[
][
]"
2016-07-31 00:24:46,747 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Adding Host request header
2016-07-31 00:24:46,871 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-8
2016-07-31 00:24:46,900 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-8
2016-07-31 00:24:46,902 DEBUG [httpclient.wire.header] - >> "User-Agent: Jakarta Commons-HttpClient/3.1[
][
]"
2016-07-31 00:24:46,903 DEBUG [httpclient.wire.header] - >> "Host: 192.168.2.111:8088[
][
]"
2016-07-31 00:24:46,903 DEBUG [httpclient.wire.header] - >> "Content-Length: 10[
][
]"
2016-07-31 00:24:46,903 DEBUG [httpclient.wire.header] - >> "Content-Type: application/x-www-form-urlencoded[
][
]"
2016-07-31 00:24:46,907 DEBUG [httpclient.wire.header] - >> "[
][
]"
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 sent
2016-07-31 00:24:47,041 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession
2016-07-31 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 active
2016-07-31 00:24:47,168 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring
2016-07-31 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: 1
2016-07-31 00:24:47,852 DEBUG [com.alibaba.druid.pool.PreparedStatementPool] - {conn-10001, pstmt-20000} enter cache
2016-07-31 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[
][
]"
2016-07-31 00:24:48,086 DEBUG [httpclient.wire.header] - << "HTTP/1.1 200 OK[
][
]"
2016-07-31 00:24:48,089 DEBUG [httpclient.wire.header] - << "Server: Apache-Coyote/1.1[
][
]"
2016-07-31 00:24:48,090 DEBUG [httpclient.wire.header] - << "Content-Type: text/html;charset=UTF-8[
][
]"
2016-07-31 00:24:48,090 DEBUG [httpclient.wire.header] - << "Content-Length: 67[
][
]"
2016-07-31 00:24:48,090 DEBUG [httpclient.wire.header] - << "Date: Sat, 30 Jul 2016 16:24:48 GMT[
][
]"
2016-07-31 00:24:48,091 DEBUG [httpclient.wire.header] - << "[
][
]"
2016-07-31 00:24:48,095 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Buffering response body
2016-07-31 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 policy
2016-07-31 00:24:48,097 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Should NOT close connection, using HTTP/1.1
2016-07-31 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}
testHttpURlConnection
2016-07-31 00:24:48,127 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession
2016-07-31 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 active
2016-07-31 00:24:48,129 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring
2016-07-31 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: 1
2016-07-31 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：

testHttpClient
2016-07-31 00:28:09,582 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.connection.timeout = 30000
2016-07-31 00:28:09,582 DEBUG [org.apache.commons.httpclient.params.DefaultHttpParams] - Set parameter http.protocol.content-charset = UTF-8
2016-07-31 00:28:09,583 DEBUG [org.apache.commons.httpclient.HttpConnection] - Open connection to 192.168.2.111:8088
2016-07-31 00:28:09,586 DEBUG [httpclient.wire.header] - >> "POST /era/user/getUserById HTTP/1.1[
][
]"
2016-07-31 00:28:09,587 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Adding Host request header
2016-07-31 00:28:09,587 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-8
2016-07-31 00:28:09,590 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Default charset used: UTF-8
2016-07-31 00:28:09,591 DEBUG [httpclient.wire.header] - >> "User-Agent: Jakarta Commons-HttpClient/3.1[
][
]"
2016-07-31 00:28:09,592 DEBUG [httpclient.wire.header] - >> "Host: 192.168.2.111:8088[
][
]"
2016-07-31 00:28:09,592 DEBUG [httpclient.wire.header] - >> "Content-Length: 10[
][
]"
2016-07-31 00:28:09,593 DEBUG [httpclient.wire.header] - >> "Content-Type: application/x-www-form-urlencoded[
][
]"
2016-07-31 00:28:09,593 DEBUG [httpclient.wire.header] - >> "[
][
]"
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 sent
2016-07-31 00:28:09,601 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession
2016-07-31 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 active
2016-07-31 00:28:09,603 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring
2016-07-31 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: 1
2016-07-31 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[
][
]"
2016-07-31 00:28:09,617 DEBUG [httpclient.wire.header] - << "HTTP/1.1 200 OK[
][
]"
2016-07-31 00:28:09,617 DEBUG [httpclient.wire.header] - << "Server: Apache-Coyote/1.1[
][
]"
2016-07-31 00:28:09,617 DEBUG [httpclient.wire.header] - << "Content-Type: text/html;charset=UTF-8[
][
]"
2016-07-31 00:28:09,618 DEBUG [httpclient.wire.header] - << "Content-Length: 67[
][
]"
2016-07-31 00:28:09,618 DEBUG [httpclient.wire.header] - << "Date: Sat, 30 Jul 2016 16:28:09 GMT[
][
]"
2016-07-31 00:28:09,618 DEBUG [httpclient.wire.header] - << "[
][
]"
2016-07-31 00:28:09,618 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Buffering response body
2016-07-31 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 policy
2016-07-31 00:28:09,619 DEBUG [org.apache.commons.httpclient.HttpMethodBase] - Should NOT close connection, using HTTP/1.1
2016-07-31 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}
testHttpURlConnection
2016-07-31 00:28:09,629 DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession
2016-07-31 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 active
2016-07-31 00:28:09,631 DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@155b4677] will not be managed by Spring
2016-07-31 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: 1
2016-07-31 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。