CharsetUtil.java

package org.gulup.utils;

/**
 * @author gulup
 * @version 创建时间：2014-5-10 下午1:04:46
 * 类说明:字符工具類
 */

import java.util.ArrayList;
import java.util.List;

import org.apache.http.protocol.HTTP;

public class CharsetUtil {
	private CharsetUtil() {
    }

    public static String toCharset(final String str, final String charset, int judgeCharsetLength) {
        try {
            String oldCharset = getEncoding(str, judgeCharsetLength);
            return new String(str.getBytes(oldCharset), charset);
        } catch (Throwable ex) {
            LogUtil.w(ex);
            return str;
        }
    }

    public static String getEncoding(final String str, int judgeCharsetLength) {
        String encode = CharsetUtil.DEFAULT_ENCODING_CHARSET;
        for (String charset : SUPPORT_CHARSET) {
            if (isCharset(str, charset, judgeCharsetLength)) {
                encode = charset;
                break;
            }
        }
        return encode;
    }

    public static boolean isCharset(final String str, final String charset, int judgeCharsetLength) {
        try {
            String temp = str.length() > judgeCharsetLength ? str.substring(0, judgeCharsetLength) : str;
            return temp.equals(new String(temp.getBytes(charset), charset));
        } catch (Throwable e) {
            return false;
        }
    }

    public static final String DEFAULT_ENCODING_CHARSET = HTTP.DEFAULT_CONTENT_CHARSET;

    public static final List<String> SUPPORT_CHARSET = new ArrayList<String>();

    static {
        SUPPORT_CHARSET.add("ISO-8859-1");

        SUPPORT_CHARSET.add("GB2312");
        SUPPORT_CHARSET.add("GBK");
        SUPPORT_CHARSET.add("GB18030");

        SUPPORT_CHARSET.add("US-ASCII");
        SUPPORT_CHARSET.add("ASCII");

        SUPPORT_CHARSET.add("ISO-2022-KR");

        SUPPORT_CHARSET.add("ISO-8859-2");

        SUPPORT_CHARSET.add("ISO-2022-JP");
        SUPPORT_CHARSET.add("ISO-2022-JP-2");

        SUPPORT_CHARSET.add("UTF-8");
    }
}