Javaの最近のブログ記事

概要

結論

調査1 - Windows で ASCII 文字列を出力

調査方法

public class Test1_2 {
	public static void main(String[] args) throws IOException {
		String s = "The quick brown fox jumps over the lazy dog";

		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < 100000; i++) {
			sb.append(s);
		}

		Charset charset = Charset.forName("iso-8859-1");

		long t = System.currentTimeMillis();

		for (int i = 0; i < 20000 * 80; i++) {
			doTest(s, charset);
		}

		long t2 = System.currentTimeMillis();
		System.out.println((t2 - t) + " msec");
	}

	private static void doTest(String s, Charset charset) throws IOException {
		OutputStreamWriter out = new OutputStreamWriter(
				new ByteArrayOutputStream(), charset);
		out.write(s);
		out.close();
	}
}

実行環境

• PC: DELL Vostro 200
• CPU: Core2Duo E8500 3.16GHz
• OS: Windows XP Pro SP2


• Java 6 update 6

測定結果

調査2 - Windows で 日本語文字列を出力

調査方法

測定結果

調査3 - Linux で ASCII 文字列を出力

実行環境

• PC: IBM Blade HS21 Model G6J
• CPU: Xeon E5450 3GHz
• OS: CentOS 5.2
• kerne: 2.6.18-92.1.6.el5PAE
• glibc: glibc-2.5-24
  
  
• Java 6 update 6

測定結果

調査4 - Linux で 日本語文字列を出力

測定結果

概要

java.net.URL を使った方法

問題再現手順

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

import javax.net.ssl.HttpsURLConnection;

public class Test1 {
    public static void main(String[] args) throws Exception {
        String href = "https://www.example.com/";
        String encoding = "UTF-8";

        URLConnection connection = new URL(href)
                .openConnection();
        HttpsURLConnection httpsconnection = (HttpsURLConnection) connection;

        int responseCode = httpsconnection.getResponseCode();
        System.out.println(responseCode);

        BufferedReader reader = new BufferedReader(new InputStreamReader(
                httpsconnection.getInputStream(), encoding));
        String buffer;
        while ((buffer = reader.readLine()) != null) {
            System.out.println(buffer);
        }
    }
}

Caused by: sun.security.provider.certpath.SunCertPathBuilderException:
     unable to find valid certification path to requested target

エラー回避方法

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
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.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

public class Test2 {
    public static void main(String[] args) throws Exception {
        String href = "https://www.example.com/";
        String encoding = "UTF-8";

        URLConnection connection = new URL(href).openConnection();
        HttpsURLConnection httpsconnection = (HttpsURLConnection) connection;

        // SSL 証明書検証をしない。
        ignoreValidateCertification(httpsconnection);

        int responseCode = httpsconnection.getResponseCode();
        System.out.println(responseCode);

        BufferedReader reader = new BufferedReader(new InputStreamReader(
                httpsconnection.getInputStream(), encoding));
        String buffer;
        while ((buffer = reader.readLine()) != null) {
            System.out.println(buffer);
        }
    }

    private static void ignoreValidateCertification(
            HttpsURLConnection httpsconnection)
            throws NoSuchAlgorithmException, KeyManagementException {
        KeyManager[] km = null;
        TrustManager[] tm = { new X509TrustManager() {
            public void checkClientTrusted(X509Certificate[] arg0, String arg1)
                    throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] arg0, String arg1)
                    throws CertificateException {
            }

            public X509Certificate[] getAcceptedIssuers() {
                return null;
            }
        } };
        SSLContext sslcontext = SSLContext.getInstance("SSL");
        sslcontext.init(km, tm, new SecureRandom());
        httpsconnection.setSSLSocketFactory(sslcontext.getSocketFactory());
    }

}

HttpClientを使ったSSLサーバへの接続

エラー再現

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.GetMethod;

public class HttpClientTest1 {
    public static void main(String[] args) throws Exception {
        String href = "https://www.example.com/";

        HttpClient httpClient = new HttpClient();

        GetMethod method = new GetMethod(href);

        int retCode = httpClient.executeMethod(method);
        System.out.println(retCode);

        byte[] buf = method.getResponseBody();
        System.out.write(buf);
    }
}

エラー回避

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.protocol.Protocol;

/**
 * テスト2: 証明書チェックを行わない。
 *
 */
public class HttpClientTest2 {

    private static void initHttpClient() {
        // 証明書チェックを行わない。
        Protocol.registerProtocol("https", new Protocol("https",
                new MySSLSocketFactory(), 443));
    }

    public static void main(String[] args) throws Exception {

        // HttpClient の初期設定。
        initHttpClient();

        String href = "https://www.example.com/";

        HttpClient httpClient = new HttpClient();

        GetMethod method = new GetMethod(href);

        int retCode = httpClient.executeMethod(method);
        System.out.println(retCode);

        byte[] buf = method.getResponseBody();
        System.out.write(buf);
    }
}

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.UnknownHostException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.SocketFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

import org.apache.commons.httpclient.ConnectTimeoutException;
import org.apache.commons.httpclient.HttpClientError;
import org.apache.commons.httpclient.params.HttpConnectionParams;
import org.apache.commons.httpclient.protocol.SecureProtocolSocketFactory;

public class MySSLSocketFactory implements SecureProtocolSocketFactory {
    private SSLContext sslcontext = null;

    private static SSLContext createEasySSLContext() {
        try {
            SSLContext context = SSLContext.getInstance("SSL");
            context.init(null, new TrustManager[] { new X509TrustManager() {
                public void checkClientTrusted(X509Certificate[] arg0,
                        String arg1) throws CertificateException {
                }

                public void checkServerTrusted(X509Certificate[] arg0,
                        String arg1) throws CertificateException {
                }

                public X509Certificate[] getAcceptedIssuers() {
                    return null;
                }
            } }, null);
            return context;
        } catch (Exception e) {
            throw new HttpClientError(e.toString());
        }
    }

    private SSLContext getSSLContext() {
        if (this.sslcontext == null) {
            this.sslcontext = createEasySSLContext();
        }
        return this.sslcontext;
    }

    @Override
    public Socket createSocket(Socket socket, String host, int port,
            boolean autoClose) throws IOException, UnknownHostException {
        return getSSLContext().getSocketFactory().createSocket(socket, host,
                port, autoClose);
    }

    @Override
    public Socket createSocket(String host, int port) throws IOException,
            UnknownHostException {
        return getSSLContext().getSocketFactory().createSocket(host, port);
    }

    @Override
    public Socket createSocket(String host, int port, InetAddress clientHost,
            int clientPort) throws IOException, UnknownHostException {
        return getSSLContext().getSocketFactory().createSocket(host, port,
                clientHost, clientPort);
    }

    @Override
    public Socket createSocket(String host, int port, InetAddress localAddress,
            int localPort, HttpConnectionParams params) throws IOException,
            UnknownHostException, ConnectTimeoutException {
        if (params == null) {
            throw new IllegalArgumentException("Parameters may not be null");
        }
        int timeout = params.getConnectionTimeout();
        SocketFactory socketfactory = getSSLContext().getSocketFactory();
        if (timeout == 0) {
            return socketfactory.createSocket(host, port, localAddress,
                    localPort);
        } else {
            Socket socket = socketfactory.createSocket();
            SocketAddress localaddr = new InetSocketAddress(localAddress,
                    localPort);
            SocketAddress remoteaddr = new InetSocketAddress(host, port);
            socket.bind(localaddr);
            socket.connect(remoteaddr, timeout);
            return socket;
        }
    }

}

概要

結論

• new Foo() の形で生成する方法は、リフレクションを使った他の方法より圧倒的に高速に動作する。
• リフレクションを使うケースの中では、static な newInstance() をリフレクションで呼ぶ方法が最も高速に動作した。

調査内容

• test-1 - new Foo()
• test-2 - Class.newInstance()
• test-3 - Constructor.newInstance()
• test-4 - Foo の static メソッド newInstance() をリフレクション経由で実行

実行結果