java实现https请求

 HttpsUtil.java

package com.lichmama.test.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

public class HttpsUtil {

    private static final class DefaultTrustManager implements X509TrustManager {
        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    }

    private static HttpsURLConnection getHttpsURLConnection(String uri, String method) throws IOException {
        SSLContext ctx = null;
        try {
            ctx = SSLContext.getInstance("TLS");
            ctx.init(new KeyManager[0], new TrustManager[] { new DefaultTrustManager() }, new SecureRandom());
        } catch (KeyManagementException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        SSLSocketFactory ssf = ctx.getSocketFactory();

        URL url = new URL(uri);
        HttpsURLConnection httpsConn = (HttpsURLConnection) url.openConnection();
        httpsConn.setSSLSocketFactory(ssf);
        httpsConn.setHostnameVerifier(new HostnameVerifier() {
            @Override
            public boolean verify(String arg0, SSLSession arg1) {
                return true;
            }
        });
        httpsConn.setRequestMethod(method);
        httpsConn.setDoInput(true);
        httpsConn.setDoOutput(true);
        return httpsConn;
    }

    private static byte[] getBytesFromStream(InputStream is) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] kb = new byte[1024];
        int len;
        while ((len = is.read(kb)) != -1) {
            baos.write(kb, 0, len);
        }
        byte[] bytes = baos.toByteArray();
        baos.close();
        is.close();
        return bytes;
    }

    private static void setBytesToStream(OutputStream os, byte[] bytes) throws IOException {
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        byte[] kb = new byte[1024];
        int len;
        while ((len = bais.read(kb)) != -1) {
            os.write(kb, 0, len);
        }
        os.flush();
        os.close();
        bais.close();
    }

    public static byte[] doGet(String uri) throws IOException {
        HttpsURLConnection httpsConn = getHttpsURLConnection(uri, "GET");
        return getBytesFromStream(httpsConn.getInputStream());
    }

    public static byte[] doPost(String uri, String data) throws IOException {
        HttpsURLConnection httpsConn = getHttpsURLConnection(uri, "POST");
        setBytesToStream(httpsConn.getOutputStream(), data.getBytes());
        return getBytesFromStream(httpsConn.getInputStream());
    }
}

下载个文件（bing今日美图）测试下：

public class TestHttps {
    
    public static void main(String[] args) throws IOException {
        String uri = "https://cn.bing.com/hpwp/356677bea977a9aa166a92ab94848f17";
        byte[] bytes = HttpsUtil.doGet(uri);
        FileOutputStream fos = new FileOutputStream("D:/bing.picture-of-day.jpg");
        fos.write(bytes);
        fos.close();
        System.out.println("done!");
    }
}

在weblogic中使用如上代码时，可能会出现ClassCastException，详情及解决方案可查看以下链接：

http://www.th7.cn/Program/java/201511/688262.shtml
http://blog.csdn.net/arvinrong/article/details/7715334