HttpClient封装工具类

在日常开发中，我们经常需要通过http协议去调用网络内容，虽然java自身提供了net相关工具包，但是其灵活性和功能总是不如人意，于是有人专门搞出一个httpclient类库，来方便进行Http操作。对于httpcore的源码研究，我们可能并没有达到这种层次，在日常开发中也只是需要的时候，在网上百度一下，然后进行调用就行。在项目中对于这个工具类库也许没有进行很好的封装。在哪里使用就写在哪些，很多地方用到，就在多个地方写。反正是复制粘贴，很方便，但是这样就会导致项目中代码冗余。所以这里简单的对httpcient的简单操作封装成一个工具类，统一放在项目的工具包中，在使用的时候直接从工具包中调用，不需要写冗余代码。

httpclient操作实例

首先需要在注意的一点是，这是基于httpclient4.5版本的，我们在使用的时候需要引入具体对应jar。下面是具体代码示：

import java.io.IOException;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.net.ssl.SSLContext;

import org.apache.commons.lang3.StringUtils;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.ssl.TrustStrategy;
import org.apache.http.util.EntityUtils;

/**
 * 基于 httpclient 4.5版本的 http工具类
 * 
 * @author 47Gamer
 * 
 */
public class HttpClientTool {

    private static final CloseableHttpClient httpClient;
    public static final String CHARSET = "UTF-8";
    // 采用静态代码块，初始化超时时间配置，再根据配置生成默认httpClient对象
    static {
        RequestConfig config = RequestConfig.custom().setConnectTimeout(60000).setSocketTimeout(15000).build();
        httpClient = HttpClientBuilder.create().setDefaultRequestConfig(config).build();
    }

    public static String doGet(String url, Map<String, String> params) {
        return doGet(url, params, CHARSET);
    }

    public static String doGetSSL(String url, Map<String, String> params) {
        return doGetSSL(url, params, CHARSET);
    }

    public static String doPost(String url, Map<String, String> params) throws IOException {
        return doPost(url, params, CHARSET);
    }

    /**
     * HTTP Get 获取内容
     * @param url 请求的url地址 ?之前的地址
     * @param params 请求的参数
     * @param charset 编码格式
     * @return 页面内容
     */
    public static String doGet(String url, Map<String, String> params, String charset) {
        if (StringUtils.isBlank(url)) {
            return null;
        }
        try {
            if (params != null && !params.isEmpty()) {
                List<NameValuePair> pairs = new ArrayList<NameValuePair>(params.size());
                for (Map.Entry<String, String> entry : params.entrySet()) {
                    String value = entry.getValue();
                    if (value != null) {
                        pairs.add(new BasicNameValuePair(entry.getKey(), value));
                    }
                }
                // 将请求参数和url进行拼接
                url += "?" + EntityUtils.toString(new UrlEncodedFormEntity(pairs, charset));
            }
            HttpGet httpGet = new HttpGet(url);
            CloseableHttpResponse response = httpClient.execute(httpGet);
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode != 200) {
                httpGet.abort();
                throw new RuntimeException("HttpClient,error status code :" + statusCode);
            }
            HttpEntity entity = response.getEntity();
            String result = null;
            if (entity != null) {
                result = EntityUtils.toString(entity, "utf-8");
            }
            EntityUtils.consume(entity);
            response.close();
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * HTTP Post 获取内容
     * @param url 请求的url地址 ?之前的地址
     * @param params 请求的参数
     * @param charset 编码格式
     * @return 页面内容
     * @throws IOException
     */
    public static String doPost(String url, Map<String, String> params, String charset) 
            throws IOException {
        if (StringUtils.isBlank(url)) {
            return null;
        }
        List<NameValuePair> pairs = null;
        if (params != null && !params.isEmpty()) {
            pairs = new ArrayList<NameValuePair>(params.size());
            for (Map.Entry<String, String> entry : params.entrySet()) {
                String value = entry.getValue();
                if (value != null) {
                    pairs.add(new BasicNameValuePair(entry.getKey(), value));
                }
            }
        }
        HttpPost httpPost = new HttpPost(url);
        if (pairs != null && pairs.size() > 0) {
            httpPost.setEntity(new UrlEncodedFormEntity(pairs, CHARSET));
        }
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpPost);
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode != 200) {
                httpPost.abort();
                throw new RuntimeException("HttpClient,error status code :" + statusCode);
            }
            HttpEntity entity = response.getEntity();
            String result = null;
            if (entity != null) {
                result = EntityUtils.toString(entity, "utf-8");
            }
            EntityUtils.consume(entity);
            return result;
        } catch (ParseException e) {
            e.printStackTrace();
        } finally {
            if (response != null)
                response.close();
        }
        return null;
    }

    /**
     * HTTPS Get 获取内容
     * @param url 请求的url地址 ?之前的地址
     * @param params 请求的参数
     * @param charset  编码格式
     * @return 页面内容
     */
    public static String doGetSSL(String url, Map<String, String> params, String charset) {
        if (StringUtils.isBlank(url)) {
            return null;
        }
        try {
            if (params != null && !params.isEmpty()) {
                List<NameValuePair> pairs = new ArrayList<NameValuePair>(params.size());
                for (Map.Entry<String, String> entry : params.entrySet()) {
                    String value = entry.getValue();
                    if (value != null) {
                        pairs.add(new BasicNameValuePair(entry.getKey(), value));
                    }
                }
                url += "?" + EntityUtils.toString(new UrlEncodedFormEntity(pairs, charset));
            }
            HttpGet httpGet = new HttpGet(url);

            // https  注意这里获取https内容，使用了忽略证书的方式，当然还有其他的方式来获取https内容
            CloseableHttpClient httpsClient = HttpClientTool.createSSLClientDefault();
            CloseableHttpResponse response = httpsClient.execute(httpGet);
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode != 200) {
                httpGet.abort();
                throw new RuntimeException("HttpClient,error status code :" + statusCode);
            }
            HttpEntity entity = response.getEntity();
            String result = null;
            if (entity != null) {
                result = EntityUtils.toString(entity, "utf-8");
            }
            EntityUtils.consume(entity);
            response.close();
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 这里创建了忽略整数验证的CloseableHttpClient对象
     * @return
     */
    public static CloseableHttpClient createSSLClientDefault() {
        try {
            SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, new TrustStrategy() {
                // 信任所有
                public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                    return true;
                }
            }).build();
            SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext);
            return HttpClients.custom().setSSLSocketFactory(sslsf).build();
        } catch (KeyManagementException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (KeyStoreException e) {
            e.printStackTrace();
        }
        return HttpClients.createDefault();
    }
}

总结

上面就是对于httpclient的简单工具类，对于httpclient，还有很多知识点需要仔细研究，后面再和大家一起来总结学习！