方法一：使用keytool手動匯入證書，為JRE環境匯入信任證書

摘自：http://www.cnblogs.com/wanghaixing/p/5630070.html

方法二：使用程式碼下載證書儲存

摘自：https://blog.csdn.net/frankcheng5143/article/details/52164939

方法三：伺服器不信任我們自己建立的證書，所以在程式碼中忽略證書信任問題。

摘自：http://mengyang.iteye.com/blog/575671

最後注意：檢查eclipse/myeclipse的JDK或JRE，是否為你匯入證書的JRE。

注意：myeclipse是自帶JDK的，JDK中自帶JRE，而我們通過命令匯入的jre是系統環境變數下path的jre。

兩者很可能不是同一個，要改myeclipse的配置。(具體操作很簡單，windows-->preferences-->搜尋jre)

推薦：

https://blog.csdn.net/ybygjy/article/details/12147281

http://www.cnblogs.com/wanghaixing/p/5630070.html#3866132

功能：把目標host證書儲存到jre/lib/security/jssecacerts檔案，親測有效

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.*;
import javax.net.ssl.*;
import java.security.cert.*;
import org.junit.Test;

public class certUtils {
	private int port = 443;
	private char[] passphrase="changeit".toCharArray();

	/**
	 * @param host 例：www.80s.tw
	 * @param port	https預設為443埠
	 * @param passphrase keyStore密碼
	 */
	public void installCert(String host, int port, char[] passphrase) {
		//檔案分隔符
		char SEP = File.separatorChar;
		//獲取jre/lib/security目錄
		File dir = new File(System.getProperty("java.home") + SEP + "lib" + SEP
				+ "security");
		//新建檔案jre/lib/security/jssecacerts,向檔案輸出時檔案才真正建立
		File file = new File(dir, "jssecacerts");
		//jssecacerts檔案不存在時，獲取jre/lib/security/cacerts檔案索引
		if (file.isFile() == false) {
			file = new File(dir, "cacerts");
		}
		System.out.println("Loading KeyStore " + file + "...");
		try {
			InputStream in = new FileInputStream(file);
			KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
			ks.load(in, passphrase);
			in.close();
			SSLContext context = SSLContext.getInstance("TLS");
			TrustManagerFactory tmf = TrustManagerFactory
					.getInstance(TrustManagerFactory.getDefaultAlgorithm());
			tmf.init(ks);
			X509TrustManager defaultTrustManager = (X509TrustManager) tmf
					.getTrustManagers()[0];
			SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
			context.init(null, new TrustManager[] { tm }, null);
			SSLSocketFactory factory = context.getSocketFactory();
			
			//與目標主機進行連線
			System.out.println("Opening connection to " + host + ":" + port);
			try {
				SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
				socket.setSoTimeout(10000);
				System.out.println("Starting SSL handshake...");
				socket.startHandshake();
				socket.close();
				System.out.println("No errors, certificate is already trusted");
			} catch (Exception e) {
				e.printStackTrace();
			}

			X509Certificate[] chain = tm.chain;
			if (chain == null) {
				return;
			}

			BufferedReader reader = new BufferedReader(new InputStreamReader(
					System.in));
			MessageDigest sha1 = MessageDigest.getInstance("SHA1");
			MessageDigest md5 = MessageDigest.getInstance("MD5");
			for (int i = 0; i < chain.length; i++) {
				X509Certificate cert = chain[i];
				sha1.update(cert.getEncoded());
				md5.update(cert.getEncoded());
			}
			// 預設證書鏈第一個
			int index = 0;
			X509Certificate cert = chain[index];
			String alias = host + "-" + (index + 1);
			ks.setCertificateEntry(alias, cert);

			// keyStore儲存到檔案jssecacerts
			File jssecacerts = new File(dir, "jssecacerts");
			OutputStream out = new FileOutputStream(jssecacerts);
			ks.store(out, passphrase);
			out.close();

			System.out.println("-----列印cert-----");
			System.out.println(cert);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	private final char[] HEXDIGITS = "0123456789abcdef".toCharArray();

	private String toHexString(byte[] bytes) {
		StringBuilder sb = new StringBuilder(bytes.length * 3);
		for (int b : bytes) {
			b &= 0xff;
			sb.append(HEXDIGITS[b >> 4]);
			sb.append(HEXDIGITS[b & 15]);
			sb.append(' ');
		}
		return sb.toString();
	}

	private class SavingTrustManager implements X509TrustManager {

		private final X509TrustManager tm;
		private X509Certificate[] chain;

		SavingTrustManager(X509TrustManager tm) {
			this.tm = tm;
		}

		public X509Certificate[] getAcceptedIssuers() {
			throw new UnsupportedOperationException();
		}

		public void checkClientTrusted(X509Certificate[] chain, String authType)
				throws CertificateException {
			throw new UnsupportedOperationException();
		}

		public void checkServerTrusted(X509Certificate[] chain, String authType)
				throws CertificateException {
			this.chain = chain;
			tm.checkServerTrusted(chain, authType);
		}
	}
}