httpclient用法

Http通信方式：
HttpURLConnection和HttpClient
HttpURLConnection是java的标准类，什么都没封装，用起来太原始，不方便
HttpClient就是一个增强版的HttpURLConnection，是apache的项目

HttpClient 两个版本：org.apache.commons.httpclient.HttpClient和org.apache.http.client.HttpClient 
commons-httpclient 是 apache-commons 项目下的一个子项目，后来被 HttpComponents 取代，后者提供了更好的性能和更大的灵活性，所以尽量使用后者。

在HttpComponents4.1.1及以后版本的jar包中，DefaultHttpClient已过时，最新的4.5版本使用的CloseableHttpClient

但是公司用的org.apache.http.client.HttpClient 4.1版本，所以暂时学习下该版本的用法（公司网络限制，代码复制下来回去再测试，未完待续）

几个不错的博文参考

http://blog.csdn.net/wangpeng047/article/details/19624529

http://blog.csdn.net/a351945755/article/details/22782229

http://blog.csdn.net/rongyongfeikai2/article/details/41659353/

http://blog.csdn.net/xiaoxian8023/article/details/49865335

http://blog.csdn.net/faye0412/article/details/6883879

https://yq.aliyun.com/articles/294

http://xiaoa7.iteye.com/blog/1262034

http://blog.sina.com.cn/s/blog_5da93c8f0100t7wo.html

http://blog.sina.com.cn/s/blog_616e189f01018rpk.html

这是针对以xml报文方式请求接口地址封装的工具类，只是初步封装

package com.focustech.ins.modules.utils;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.*;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.*;
import org.apache.http.util.EntityUtils;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.util.HashMap;

public class HttpUtil {
    private static Log                logger                = LogFactory.getLog(HttpUtil.class);
    // 总连接数
    private static Integer            maxTotal            = Integer.valueOf(HttpCfgUtil.getProperty("maxTotal"));
    // 每个服务器的默认连接数,必须指定，否者默认是2
    private static Integer            defaultMaxPerRoute    = Integer
            .valueOf(HttpCfgUtil.getProperty("defaultMaxPerRoute"));
    // 指定服务器的地址,每个指定服务器地址用逗号隔开
    private static String            routeHost            = HttpCfgUtil.getProperty("routeHost");
    // 指定服务器的连接数，每个指定服务器连接数用逗号隔开
    private static String            maxForRoute            = HttpCfgUtil.getProperty("maxForRoute");
    // 默认编码
    private static String            defaultEncode        = HttpCfgUtil.getProperty("defaultEncode");
    // 设定连接等待时间
    private static Integer            so_timeout            = Integer.valueOf(HttpCfgUtil.getProperty("so_timeout"));
    // 设定连接超时时间
    private static Integer            connection_timeout    = Integer
            .valueOf(HttpCfgUtil.getProperty("connection_timeout"));

    // 这几个对象都是通用设置，不存在线程安全问题，所以可以共用
    private static HttpParams        httpParams            = createHttpParams();
    private static SSLContext        sslContext            = createIgnoreVerifySSL();
    private static SchemeRegistry    schemeRegistry        = new SchemeRegistry();
    static {
        // 设置访问协议
        schemeRegistry.register(new Scheme("http", 80, new PlainSocketFactory()));
        schemeRegistry.register(new Scheme("https", 443,
                new SSLSocketFactory(sslContext, SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER)));
    }
    // 连接管理器，ThreadSafeClientConnManager线程安全并且默认支持连接池
    private ThreadSafeClientConnManager            tscm    = null;
    // 一个HttpClient维护一个池
    private HttpClient                            client    = null;
    private static HashMap<String, HttpUtil>    cs        = new HashMap<String, HttpUtil>();

    // 根据公司编码创建池
    private HttpUtil() {
        tscm = new ThreadSafeClientConnManager(schemeRegistry);
        client = new DefaultHttpClient(tscm, httpParams);
        initClientConnManager(tscm);
    }

    // 调用此类的接口才会创建池
    // 按照接口地址去掉接口类型所得编码创建连接池 823001_01_04----》82300104
    public static HttpUtil getInstance(String fixCode) {
        StringBuilder comAndNum = new StringBuilder(8);
        String codes[] = fixCode.split("_");
        comAndNum.append(codes[0]).append(codes[2]);
        HttpUtil e = cs.get(comAndNum);
        if (e == null) {
            e = new HttpUtil();
            cs.put(comAndNum.toString(), e);
        }
        return e;
    }

    // GET请求方式,默认请求头，utf-8编码
    public String getMethod(String URI) throws IOException, URISyntaxException {
        HttpGet get = getHttpGet(URI);
        String result = getResponseEntity(get);
        return result;
    }

    // GET请求方式,默认请求头，自定义编码
    public String getMethod(String URI, String encode) throws IOException, URISyntaxException {
        HttpGet get = getHttpGet(URI);
        String result = getResponseEntity(get);
        return result;
    }

    // GET请求方式,自定义请求头，utf-8编码
    public String getMethod(HttpGet get) throws IOException {
        String result = getResponseEntity(get);
        return result;
    }

    // GET请求方式,自定义请求头，指定编码
    public String getMethod(HttpGet get, String encode) throws IOException {
        initHeaders(get, encode);
        String result = getResponseEntity(get);
        return result;
    }

    // POST请求方式,默认请求头,utf-8编码
    public String postMethod(String URI, String msg) throws URISyntaxException, IOException {
        HttpPost post = getHttpPost(URI);
        HttpEntity requestEntity = setRequestEntity(msg);
        post.setEntity(requestEntity);
        String result = getResponseEntity(post);
        return result;
    }

    // POST请求方式,默认请求头，指定编码
    public String postMethod(String URI, String msg, String encode) throws URISyntaxException, IOException {
        HttpPost post = getHttpPost(URI, encode);
        HttpEntity requestEntity = setRequestEntity(msg, encode);
        post.setEntity(requestEntity);
        String result = getResponseEntity(post);
        return result;
    }

    // POST请求方式 流-》字节,默认请求头，utf-8编码
    public byte[] postMethodToByte(String URI) throws URISyntaxException, IOException {
        HttpPost post = getHttpPost(URI);
        byte[] content = getResponseEntityToByte(post);
        return content;
    }

    // POST请求方式 流-》字节,默认请求头，指定编码
    public byte[] postMethodToByte(String URI, String encode) throws URISyntaxException, IOException {
        HttpPost post = getHttpPost(URI, encode);
        byte[] content = getResponseEntityToByte(post);
        return content;
    }

    // POST请求方式,自定义请求头，utf-8编码
    public String postMethod(HttpPost post, String msg) throws IOException {
        HttpEntity requestEntity = setRequestEntity(msg);
        post.setEntity(requestEntity);
        String result = getResponseEntity(post);
        return result;
    }

    // POST请求方式,自定义请求头，指定编码
    public String postMethod(HttpPost post, String msg, String encode) throws IOException {
        initHeaders(post, encode);
        HttpEntity requestEntity = setRequestEntity(msg, encode);
        post.setEntity(requestEntity);
        String result = getResponseEntity(post);
        return result;
    }

    // 获取HttpGet对象,utf-8编码
    public HttpGet getHttpGet(String URI) throws URISyntaxException {
        HttpGet get = new HttpGet(new URI(URI));
        initHeaders(get);
        return get;
    }

    // 获取HttpGet对象,指定编码
    public HttpGet getHttpGet(String URI, String encode) throws URISyntaxException {
        HttpGet get = new HttpGet(new URI(URI));
        initHeaders(get, encode);
        return get;
    }

    // 获取HttpPost对象，utf-8编码
    public HttpPost getHttpPost(String URI) throws URISyntaxException {
        HttpPost post = new HttpPost(new URI(URI));
        initHeaders(post);
        return post;
    }

    // 获取HttpPost对象，指定编码
    public HttpPost getHttpPost(String URI, String encode) throws URISyntaxException {
        HttpPost post = new HttpPost(new URI(URI));
        initHeaders(post, encode);
        return post;
    }

    // 获取GET/POST响应内容
    public String getResponseEntity(HttpRequestBase requestMethod) throws IOException {
        HttpEntity responseEntity = null;
        String result = null;
        HttpResponse response = null;
        try {
            response = client.execute(requestMethod);
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                responseEntity = response.getEntity();
            }
            if (responseEntity != null)
                result = EntityUtils.toString(responseEntity);
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            EntityUtils.consume(responseEntity);
        }
        return result;
    }

    // 获取GET/POST响应内容流-》字节
    public byte[] getResponseEntityToByte(HttpRequestBase requestMethod) throws IOException {
        HttpEntity responseEntity = null;
        byte[] content = null;
        HttpResponse response = null;
        try {
            response = client.execute(requestMethod);
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                responseEntity = response.getEntity();
            }
            if (responseEntity != null)
                content = EntityUtils.toByteArray(responseEntity);
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            EntityUtils.consume(responseEntity);
        }
        return content;
    }

    // 设置POST请求体，msg表示报文,使用默认编码utf-8
    public HttpEntity setRequestEntity(String msg) throws UnsupportedEncodingException {
        HttpEntity entity = null;
        if (msg != null)
            entity = new StringEntity(msg, defaultEncode);
        return entity;
    }

    // 设置POST请求体，msg表示报文，使用指定编码
    public HttpEntity setRequestEntity(String msg, String encode) throws UnsupportedEncodingException {
        HttpEntity entity = null;
        if (msg != null)
            entity = new StringEntity(msg, encode);
        return entity;
    }

    // 设置默认的请求头，utf-8编码(可通过获取requestMethod自定义请求头)
    public void initHeaders(HttpRequestBase requestMethod) {
        requestMethod.setHeader("Content-Type", "text/xml;charset=" + defaultEncode);
        requestMethod.setHeader("Cache-Control", "no-cache");
        requestMethod.setHeader("Pragma", "no-cache");
        requestMethod.setHeader("Content-Type", "Expires");
        requestMethod.setHeader("Accept-Charset", defaultEncode);
    }

    // 设置默认的请求头,指定编码
    public void initHeaders(HttpRequestBase requestMethod, String encode) {
        requestMethod.setHeader("Content-Type", "text/xml;charset=" + encode);
        requestMethod.setHeader("Cache-Control", "no-cache");
        requestMethod.setHeader("Pragma", "no-cache");
        requestMethod.setHeader("Content-Type", "Expires");
        requestMethod.setHeader("Accept-Charset", encode);
    }

    // 初始化ClientConnManager，设定并发数，不设定给出默认值
    public void initClientConnManager(ThreadSafeClientConnManager tscm) {
        if (maxTotal != null)
            tscm.setMaxTotal(maxTotal);
        if (defaultMaxPerRoute != null)
            tscm.setDefaultMaxPerRoute(defaultMaxPerRoute);
        // 处理指定服务器的连接数设置
        if (routeHost != null && !routeHost.equals("")) {
            String routeHosts[] = routeHost.split(",");
            String maxForRoutes[] = maxForRoute.split(",");
            for (int i = 0; i < routeHosts.length; i++) {
                String routeHost = routeHosts[i];
                Integer maxForRoute = Integer.valueOf(maxForRoutes[i]);
                if (maxForRoute == null)
                    break;
                HttpHost host = new HttpHost(routeHosts[i], maxForRoute);
                tscm.setMaxForRoute(new HttpRoute(host), maxForRoute);
            }
        }
    }

    // 创建HttpParams对象并指定超时时间
    public static HttpParams createHttpParams() {
        HttpParams httpParams = new BasicHttpParams();
        // 设定连接等待时间
        if (so_timeout != null)
            httpParams.setParameter(HttpConnectionParams.SO_TIMEOUT, so_timeout);
        // 设定连接超时时间
        if (connection_timeout != null)
            httpParams.setParameter(HttpConnectionParams.CONNECTION_TIMEOUT, connection_timeout);
        return httpParams;
    }

    // 创建SSLContext对象用于绕过SSL验证
    public static SSLContext createIgnoreVerifySSL() {
        SSLContext sc = null;
        try {
            sc = SSLContext.getInstance("TLS");
            // 实现一个X509TrustManager接口，重写验证方法用于绕过SSL验证
            X509TrustManager trustManager = new X509TrustManager() {
                @Override
                public void checkClientTrusted(java.security.cert.X509Certificate[] paramArrayOfX509Certificate,
                        String paramString) throws CertificateException {
                }

                @Override
                public void checkServerTrusted(java.security.cert.X509Certificate[] paramArrayOfX509Certificate,
                        String paramString) throws CertificateException {
                }

                @Override
                public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                    return null;
                }
            };
            sc.init(null, new TrustManager[] { trustManager }, null);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (KeyManagementException e) {
            e.printStackTrace();
        }
        return sc;
    }

    // 关闭ThreadSafeClientConnManager,此方法会关闭一个池中所有连接，不要调用
    public void release() {
        if (tscm != null) {
            tscm.shutdown();
        }
    }

}