URLからコンテンツ取得および文字コード変換

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ContentRetriever.java
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import java.io.*;
import java.net.*;

/**
$Id: content-retriever.html,v 1.1 2009/06/22 16:12:07 kishi Exp kishi $
*/
public class ContentRetriever {
    private String urlString;
    private String outputFileName;

    public ContentRetriever( String urlString, String outputFileName ) {
        this.urlString = urlString;
        this.outputFileName = outputFileName;
    }

    public void retrieve() {
        try {

            // URL の作成
            URL url = new URL( urlString );

            // コネクトして、HttpURLConnection の作成
            HttpURLConnection connection = ( HttpURLConnection ) url.openConnection();
            connection.setRequestMethod( "GET" );

            System.out.println( "\n\n===============================================================================" );
            System.out.println( "コンテントタイプは " + connection.getContentType() + " です。" );
            System.out.println( "レスポンスコードは " + connection.getResponseCode() + " です。" );
            System.out.println( "===============================================================================" );

            // 出力ストリーム
            BufferedOutputStream bos = new BufferedOutputStream( new FileOutputStream( outputFileName ) );

            // 入力ストリーム
            BufferedInputStream bis = new BufferedInputStream( connection.getInputStream() );
            int size = bis.available();

            byte[] buf = new byte[ size ];

            int len = 0;
            while ( ( len = bis.read( buf ) ) > 0 ) {
                System.out.println( "len=" + len );
                bos.write( buf, 0, len );
            }

            bis.close();
            bos.close();

        } catch ( Exception e ) {
            e.printStackTrace();
        }
    }

    static public void main( String[] args ) {

        if ( args.length != 2 ) {
            System.err.println( "Usage: java Test1 [URL] [outputFileName]" );
            System.exit( 1 );
        }

        String targetUrl = args[ 0 ];
        String outputFileName = args[ 1 ];

        ContentRetriever retriever = new ContentRetriever( targetUrl, outputFileName );
        retriever.retrieve();

    }

}
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GenericDecoder.java
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import java.io.*;
import java.nio.*;
import java.nio.charset.*;

/**
$Id: content-retriever.html,v 1.1 2009/06/22 16:12:07 kishi Exp kishi $
*/

public class GenericDecoder {

    private String filename;
    private String sourceEncoding;

    public GenericDecoder( String filename, String sourceEncoding ) {

        this.filename = filename;
        this.sourceEncoding = sourceEncoding;

    }

    public void decode() {
        try {

            //==========================================================================
            // 入力ストリーム側の文字エンコーディングを事前にしておく必要がある
            // なんとかならんか・・・
            //==========================================================================
            Charset charset = Charset.forName( sourceEncoding );

            BufferedInputStream bis = new BufferedInputStream( new FileInputStream( filename ) );

            int size = bis.available();
            byte[] buf = new byte[ size ];

            int len = 0;
            while ( ( len = bis.read( buf ) ) > 0 ) {
                byte[] before = new byte[ len ];
                for ( int i = 0;i < len;i++ ) {
                    before[ i ] = buf[ i ];
                }

                CharBuffer result = charset.decode( ByteBuffer.wrap( before ) );
                // 標準出力に出力
                System.out.print( result.toString() );
            }

            bis.close();
        } catch ( Exception e ) {
            e.printStackTrace();
        }

    }

    static public void main( String[] args ) {
        if ( args.length != 2 ) {
            System.out.println( "Usage: java GenericDecoder [inputFileName] [sourceEncoding]" );
            System.exit( 1 );
        }

        GenericDecoder decoder = new GenericDecoder( args[ 0 ], args[ 1 ] );
        decoder.decode();

    }
}