stringutils.java

非常棒的java数据库

            if (c == separatorChar) {
                String e = buff.toString();
                list.add(trim ? e.trim() : e);
                buff.setLength(0);
            } else if (c == '\\' && i < s.length() - 1) {
                buff.append(s.charAt(++i));
            } else {
                buff.append(c);
            }
        }
        String e = buff.toString();
        list.add(trim ? e.trim() : e);
        String[] array = new String[list.size()];
        list.toArray(array);
        return array;
    }

    public static String arrayCombine(String[] list, char separatorChar) {
        StringBuffer buff = new StringBuffer(5 * list.length);
        for (int i = 0; i < list.length; i++) {
            if (i > 0) {
                buff.append(separatorChar);
            }
            String s = list[i];
            if (s == null) {
                s = "";
            }
            for (int j = 0; j < s.length(); j++) {
                char c = s.charAt(j);
                if (c == '\\' || c == separatorChar) {
                    buff.append('\\');
                }
                buff.append(c);
            }
        }
        return buff.toString();
    }

    /**
     * Formats a date using a format string
     */
    public static String formatDateTime(Date date, String format, String locale, String timezone) throws SQLException {
        SimpleDateFormat dateFormat = getDateFormat(format, locale, timezone);
        synchronized (dateFormat) {
            return dateFormat.format(date);
        }
    }

    /**
     * Parses a date using a format string
     */
    public static Date parseDateTime(String date, String format, String locale, String timezone) throws SQLException {
        SimpleDateFormat dateFormat = getDateFormat(format, locale, timezone);
        try {
            synchronized (dateFormat) {
                return dateFormat.parse(date);
            }
        } catch (ParseException e) {
            throw Message.getSQLException(ErrorCode.PARSE_ERROR_1, new String[]{date}, e);
        }
    }

    private static SimpleDateFormat getDateFormat(String format, String locale, String timezone) throws SQLException {
        try {
            // currently, a new instance is create for each call
            // however, could cache the last few instances
            SimpleDateFormat df;
            if (locale == null) {
                df = new SimpleDateFormat(format);
            } else {
//#ifdef JDK14
                Locale l = new Locale(locale);
//#endif
//#ifdef JDK13
/*
                Locale l = new Locale(locale, "");
*/
//#endif
                df = new SimpleDateFormat(format, l);
            }
            if (timezone != null) {
                df.setTimeZone(TimeZone.getTimeZone(timezone));
            }
            return df;
        } catch (Exception e) {
            throw Message.getSQLException(ErrorCode.PARSE_ERROR_1, new String []{format + "/" + locale + "/" + timezone}, e);
        }
    }

    /**
     * Creates an XML attribute of the form name="value".
     * A single space is prepended to the name,
     * so that multiple attributes can be concatenated.
     * @param name
     * @param value
     * @return the attribute
     */
    public static String xmlAttr(String name, String value) {
        return " " + name + "=\"" + xmlText(value) + "\"";
    }

    /**
     * Create an XML node with optional attributes and content.
     * The data is indented with 4 spaces if it contains a newline character.
     *
     * @param name the element name
     * @param attributes the attributes (may be null)
     * @param content the content (may be null)
     * @return the node
     */
    public static String xmlNode(String name, String attributes, String content) {
        String start = attributes == null ? name : name + attributes;
        if (content == null) {
            return "<" + start + "/>\n";
        } else {
            if (content.indexOf('\n') >= 0) {
                content = "\n" + indent(content);
            }
            return "<" + start + ">" + content + "</" + name + ">\n";
        }
    }

    /**
     * Indents a string with 4 spaces.
     * @param s the string
     * @return the indented string
     */
    public static String indent(String s) {
        return indent(s, 4);
    }

    /**
     * Indents a string with spaces.
     * @param s the string
     * @param spaces the number of spaces
     * @return the indented string
     */
    public static String indent(String s, int spaces) {
        StringBuffer buff = new StringBuffer(s.length() + spaces);
        for (int i = 0; i < s.length();) {
            for (int j = 0; j < spaces; j++) {
                buff.append(' ');
            }
            int n = s.indexOf('\n', i);
            n = n < 0 ? s.length() : n + 1;
            buff.append(s.substring(i, n));
            i = n;
        }
        if (!s.endsWith("\n")) {
            buff.append('\n');
        }
        return buff.toString();
    }

    /**
     * Escapes a comment.
     * If the data contains '--', it is converted to '- -'.
     * The data is indented with 4 spaces if it contains a newline character.
     *
     * @param data
     * @return <!-- data -->
     */
    public static String xmlComment(String data) {
        int idx = 0;
        while (true) {
            idx = data.indexOf("--", idx);
            if (idx < 0) {
                break;
            }
            data = data.substring(0, idx + 1) + " " + data.substring(idx + 1);
        }
        // must have a space at the beginning and at the end,
        // otherwise the data must not contain '-' as the first/last character
        if (data.indexOf('\n') >= 0) {
            return "<!--\n" + indent(data) + "-->\n";
        } else {
            return "<!-- " + data + " -->\n";
        }
    }

    /**
     * Converts the data to a CDATA element.
     * If the data contains ']]>', it is escaped as a text element.
     * @param data
     * @return <![CDATA[data]]>
     */
    public static String xmlCData(String data) {
        if (data.indexOf("]]>") >= 0) {
            return xmlText(data);
        }
        boolean newline = data.endsWith("\n");
        data = "<![CDATA[" + data + "]]>";
        return newline ? data + "\n" : data;
    }

    /**
     * Returns <?xml version="1.0"?>
     * @return <?xml version="1.0"?>
     */
    public static String xmlStartDoc() {
        return "<?xml version=\"1.0\"?>\n";
    }

    /**
     * Escapes an XML text element.
     *
     * @param text
     * @return the escaped text
     */
    public static String xmlText(String text) {
        StringBuffer buff = new StringBuffer(text.length());
        for (int i = 0; i < text.length(); i++) {
            char ch = text.charAt(i);
            switch (ch) {
            case '<':
                buff.append("&lt;");
                break;
            case '>':
                buff.append("&gt;");
                break;
            case '&':
                buff.append("&amp;");
                break;
            case '\'':
                buff.append("&apos;");
                break;
            case '\"':
                buff.append("&quot;");
                break;
            case '\r':
            case '\n':
            case '\t':
                buff.append(ch);
                break;
            default:
                if (ch < ' ' || ch > 127) {
                    buff.append("&#x");
                    buff.append(Integer.toHexString(ch));
                    buff.append(';');
                } else {
                    buff.append(ch);
                }
            }
        }
        return buff.toString();
    }

    public static String replaceAll(String s, String before, String after) {
        int index = 0;
        while (true) {
            int next = s.indexOf(before, index);
            if (next < 0) {
                return s;
            }
            s = s.substring(0, next) + after + s.substring(next + before.length());
            index = next + after.length();
        }
    }

    public static String quoteIdentifier(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);
            }
            buff.append(c);
        }
        return buff.append('\"').toString();
    }

    /**
     * Check if a String is null or empty (the length is null).
     *
     * @return true if it is null or empty
     */
    public static boolean isNullOrEmpty(String s) {
        return s == null || s.length() == 0;
    }

    public static String quoteRemarkSQL(String sql) {
        while (true) {
            int idx = sql.indexOf("*/");
            if (idx < 0) {
                break;
            }
            sql = sql.substring(0, idx) + "++/" + sql.substring(idx + 2);
        }
        while (true) {
            int idx = sql.indexOf("/*");
            if (idx < 0) {
                break;
            }
            sql = sql.substring(0, idx) + "/++" + sql.substring(idx + 2);
        }
        return sql;
    }

    /**
     * Pad a string. This method is used for the SQL function RPAD and LPAD.
     * 
     * @param string the original string
     * @param n the target length
     * @param padding the padding string
     * @param right true if the padding should be appended at the end
     * @return the padded string
     */
    public static String pad(String string, int n, String padding, boolean right) {
        if (n < 0) {
            n = 0;
        }
        if (n < string.length()) {
            return string.substring(0, n);
        } else if (n == string.length()) {
            return string;
        }
        char paddingChar;
        if (padding == null || padding.length() == 0) {
            paddingChar = ' ';
        } else {
            paddingChar = padding.charAt(0);
        }
        StringBuffer buff = new StringBuffer(n);
        n -= string.length();
        if (right) {
            buff.append(string);
        }
        for (int i = 0; i < n; i++) {
            buff.append(paddingChar);
        }
        if (!right) {
            buff.append(string);
        }
        return buff.toString();
    }

}