stringutils.java

非常棒的java数据库

/*
 * Copyright 2004-2008 H2 Group. Licensed under the H2 License, Version 1.0
 * (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.util;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

import org.h2.constant.ErrorCode;
import org.h2.constant.SysProperties;
import org.h2.engine.Constants;
import org.h2.message.Message;

/**
 * A few String utility functions.
 */
public class StringUtils {

    public static boolean equals(String a, String b) {
        if (a == null) {
            return b == null;
        }
        return a.equals(b);
    }

    public static String toUpperEnglish(String s) {
        return s.toUpperCase(Locale.ENGLISH);
    }

    public static String toLowerEnglish(String s) {
        return s.toLowerCase(Locale.ENGLISH);
    }

    public static String getDefaultCharset() {
        return SysProperties.FILE_ENCODING;
    }

    public static String quoteStringSQL(String s) {
        StringBuffer buff = new StringBuffer(s.length() + 2);
        buff.append('\'');
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '\'') {
                buff.append(c);
            } else if (c < ' ' || c > 127) {
                // need to start from the beginning because maybe there was a \
                // that was not quoted
                return "STRINGDECODE(" + quoteStringSQL(javaEncode(s)) + ")";
            }
            buff.append(c);
        }
        buff.append('\'');
        return buff.toString();
    }

    public static String javaEncode(String s) {
        StringBuffer buff = new StringBuffer(s.length());
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            switch (c) {
//            case '\b':
//                // BS backspace
//                // not supported in properties files
//                buff.append("\\b");
//                break;
            case '\t':
                // HT horizontal tab
                buff.append("\\t");
                break;
            case '\n':
                // LF linefeed
                buff.append("\\n");
                break;
            case '\f':
                // FF form feed
                buff.append("\\f");
                break;
            case '\r':
                // CR carriage return
                buff.append("\\r");
                break;
            case '"':
                // double quote
                buff.append("\\\"");
                break;
            case '\\':
                // backslash
                buff.append("\\\\");
                break;
            default:
                int ch = (c & 0xffff);
                if (ch >= ' ' && (ch < 0x80)) {
                    buff.append(c);
                // not supported in properties files
                // } else if(ch < 0xff) {
                // buff.append("\\");
                // // make sure it's three characters (0x200 is octal 1000)
                // buff.append(Integer.toOctalString(0x200 | ch).substring(1));
                } else {
                    buff.append("\\u");
                    // make sure it's four characters
                    buff.append(Integer.toHexString(0x10000 | ch).substring(1));
                }
            }
        }
        return buff.toString();
    }

    public static String addAsterisk(String s, int index) {
        if (s != null && index < s.length()) {
            s = s.substring(0, index) + "[*]" + s.substring(index);
        }
        return s;
    }

    private static SQLException getFormatException(String s, int i) {
        return Message.getSQLException(ErrorCode.STRING_FORMAT_ERROR_1, addAsterisk(s, i));
    }

    public static String javaDecode(String s) throws SQLException {
        StringBuffer buff = new StringBuffer(s.length());
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '"') {
                break;
            } else if (c == '\\') {
                if (i >= s.length()) {
                    throw getFormatException(s, s.length() - 1);
                }
                c = s.charAt(++i);
                switch (c) {
                case 't':
                    buff.append('\t');
                    break;
                case 'r':
                    buff.append('\r');
                    break;
                case 'n':
                    buff.append('\n');
                    break;
                case 'b':
                    buff.append('\b');
                    break;
                case 'f':
                    buff.append('\f');
                    break;
                case '#':
                    // for properties files
                    buff.append('#');
                    break;
                case '=':
                    // for properties files
                    buff.append('=');
                    break;
                case ':':
                    // for properties files
                    buff.append(':');
                    break;
                case '"':
                    buff.append('"');
                    break;
                case '\\':
                    buff.append('\\');
                    break;
                case 'u': {
                    try {
                        c = (char) (Integer.parseInt(s.substring(i + 1, i + 5), 16));
                    } catch (NumberFormatException e) {
                        throw getFormatException(s, i);
                    }
                    i += 4;
                    buff.append(c);
                    break;
                }
                default:
                    if (c >= '0' && c <= '9') {
                        try {
                            c = (char) (Integer.parseInt(s.substring(i, i + 3), 8));
                        } catch (NumberFormatException e) {
                            throw getFormatException(s, i);
                        }
                        i += 2;
                        buff.append(c);
                    } else {
                        throw getFormatException(s, i);
                    }
                }
            } else {
                buff.append(c);
            }
        }
        return buff.toString();
    }

    public static String quoteJavaString(String s) {
        if (s == null) {
            return "null";
        } else {
            return "\"" + javaEncode(s) + "\"";
        }
    }

    public static byte[] utf8Encode(String s) throws SQLException {
        try {
            // TODO UTF8: String.getBytes("UTF-8") only returns 1 byte for
            // 0xd800-0xdfff
            return s.getBytes(Constants.UTF8);
        } catch (UnsupportedEncodingException e) {
            throw Message.convert(e);
        }
    }

    public static String utf8Decode(byte[] utf8) {
        try {
            return new String(utf8, Constants.UTF8);
        } catch (UnsupportedEncodingException e) {
            throw Message.convertToInternal(e);
        }
    }

    public static String utf8Decode(byte[] bytes, int offset, int length) {
        try {
            return new String(bytes, offset, length, Constants.UTF8);
        } catch (UnsupportedEncodingException e) {
            throw Message.convertToInternal(e);
        }
    }

    public static String quoteJavaStringArray(String[] array) {
        if (array == null) {
            return "null";
        }
        StringBuffer buff = new StringBuffer(5 * array.length);
        buff.append("new String[]{");
        for (int i = 0; i < array.length; i++) {
            if (i > 0) {
                buff.append(", ");
            }
            buff.append(quoteJavaString(array[i]));
        }
        buff.append("}");
        return buff.toString();
    }

    public static String quoteJavaIntArray(int[] array) {
        if (array == null) {
            return "null";
        }
        StringBuffer buff = new StringBuffer(2 * array.length);
        buff.append("new int[]{");
        for (int i = 0; i < array.length; i++) {
            if (i > 0) {
                buff.append(", ");
            }
            buff.append(array[i]);
        }
        buff.append("}");
        return buff.toString();
    }

    public static String enclose(String s) {
        if (s.startsWith("(")) {
            return s;
        } else {
            return "(" + s + ")";
        }
    }

    public static String unEnclose(String s) {
        if (s.startsWith("(") && s.endsWith(")")) {
            return s.substring(1, s.length() - 1);
        } else {
            return s;
        }
    }

    public static String urlEncode(String s) {
//#ifdef JDK14
        try {
            return URLEncoder.encode(s, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return s;
        }
//#endif
//#ifdef JDK13
/*
        return URLEncoder.encode(s);
*/
//#endif
//        byte[] utf = utf8Encode(s);
//        StringBuffer buff = new StringBuffer(utf.length);
//        for(int i=0; i<utf.length; i++) {
//
//            buff.append()
//        }
    }

    public static String urlDecode(String encoded) throws SQLException {
        byte[] buff = new byte[encoded.length()];
        int j = 0;
        for (int i = 0; i < encoded.length(); i++) {
            char ch = encoded.charAt(i);
            if (ch == '+') {
                buff[j++] = ' ';
            } else if (ch == '%') {
                buff[j++] = (byte) Integer.parseInt(encoded.substring(i + 1, i + 3), 16);
                i += 2;
            } else {
                if (SysProperties.CHECK && (ch > 127 || ch < ' ')) {
                    throw new IllegalArgumentException("unexpected char " + (int) ch + " decoding " + encoded);
                }
                buff[j++] = (byte) ch;
            }
        }
        String s = utf8Decode(buff, 0, j);
        return s;
    }

    public static String[] arraySplit(String s, char separatorChar, boolean trim) {
        if (s == null) {
            return null;
        }
        if (s.length() == 0) {
            return new String[0];
        }
        ArrayList list = new ArrayList();
        StringBuffer buff = new StringBuffer(s.length());
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);