【转】能保存Properties文件注释的Properties工具类

原文：https://www.iteye.com/blog/brokendreams-1932875

package com.vrv.util; 

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/** 
 *   CommentedProperties
 *   针对Properties进行扩展的工具类
 *   
 *   扩展的两个主要功能:
 *   1.对Properties文件中注释的保存。
 *       CommentedProperties在读取和保存Properties文件时,会将其注释
 *       一起读取保存。CommentedProperties中会提供方法来根据key获取
 *       相应注释。在CommentedProperties中添加一个K-V对时，也会提供
 *       添加相应注释的方法。
 *       
 *   2.对Properties文件中Key值顺序的保证。
 *       CommentedProperties会保证Key的顺序。从一个Properties文件中
 *       读取所有K-V对，保存到另一个Properties文件时，Key的顺序不会
 *       改变。
 *       
 *
 * @author BrokenDreams
 */
public class CommentedProperties{

    /**
     * 内部属性表
     */
    private final Properties props;

    /**
     * 保存key与comment的映射，
     * 同时利用这个映射来保证key的顺序。
     */
    private final LinkedHashMap<String, String> keyCommentMap = new LinkedHashMap<String, String>();

    private static final String BLANK = "";

    public CommentedProperties() {
        super();
        props = new Properties();
    }

    public CommentedProperties(Properties defaults) {
        super();
        props = new Properties(defaults);
    }

    /**
     * 设置一个属性，如果key已经存在，那么将其对应value值覆盖。
     * @param key
     * @param value
     * @return
     */
    public String setProperty(String key, String value) {
        return setProperty(key, value, BLANK);
    }

    /**
     * 设置一个属性，如果key已经存在，那么将其对应value值覆盖。
     * 
     * @param key 键
     * @param value 与键对应的值
     * @param comment 对键值对的说明
     * @return
     */
    public synchronized String setProperty(String key, String value, String comment){
        Object oldValue = props.setProperty(key, value);
        if(BLANK.equals(comment)){
            if(!keyCommentMap.containsKey(key)){
                keyCommentMap.put(key, comment);
            }
        }else{
            keyCommentMap.put(key, comment);
        }
        return (String)oldValue;
    }
    
    /**
     * 根据key获取属性表中相应的value。
     * 
     * @param key
     * @return
     */
    public String getProperty(String key) {
        return props.getProperty(key);
    }

    /**
     * 根据key获取属性表中相应的value。
     * 如果没找到相应的value，返回defaultValue。
     * 
     * @param key
     * @param defaultValue
     * @return
     */
    public String getProperty(String key, String defaultValue) {
        return props.getProperty(key, defaultValue);
    }

    /**
     * 从一个字符流中读取属性到属性表中
     * 
     * @param reader
     * @throws IOException
     */
    public synchronized void load(Reader reader) throws IOException {
        load0(new LineReader(reader));
    }

    /**
     * 从一个字节流中读取属性到属性表中
     * 
     * @param inStream
     * @throws IOException
     */
    public synchronized void load(InputStream inStream) throws IOException {
        load0(new LineReader(inStream));
    }

    /**
     * 从一个字节流中读取属性到属性表中
     * 
     * @param inStream
     * @param charset
     * @throws IOException
     */
    public synchronized void load(InputStream inStream, String charset) throws IOException {
        InputStreamReader reader = new InputStreamReader(inStream, charset);
        load0(new LineReader(reader));
    }

    /**
     * 从一个文件中读取属性到属性表中
     * 
     * @param file 属性文件
     * @param charset 字符集
     * @throws IOException
     */
    public synchronized void load(File file, String charset) throws IOException {
        FileInputStream inputStream = new FileInputStream(file);
        InputStreamReader reader = new InputStreamReader(inputStream, charset);
        load0(new LineReader(reader));
    }

    /**
     * 从一个文件中读取属性到属性表中
     * 默认字符集为utf-8
     * 
     * @param file 属性文件
     * @throws IOException
     */
    public synchronized void load(File file) throws IOException {
        FileInputStream inputStream = new FileInputStream(file);
        InputStreamReader reader = new InputStreamReader(inputStream, "utf-8");
        load0(new LineReader(reader));
    }
    
    /**
     * 将属性表中的属性写到字符流里面。
     * 
     * @param writer
     * @throws IOException
     */
    public void store(Writer writer) throws IOException {
        store0((writer instanceof BufferedWriter)?(BufferedWriter)writer
                : new BufferedWriter(writer),false);
    }

    /**
     * 将属性表中的属性写到字节流里面。
     * 
     * @param out
     * @throws IOException
     */
    public void store(OutputStream out) throws IOException {
        store0(new BufferedWriter(new OutputStreamWriter(out, "utf-8")),true);
    }

    /**
     * 如果属性表中某个key对应的value值和参数value相同
     * 那么返回true，否则返回false。
     * 
     * @param value
     * @return
     */
    public boolean containsValue(String value) {
        return props.containsValue(value);
    }

    /**
     * 如果属性表中存在参数key，返回true，否则返回false。
     * 
     * @param key
     * @return
     */
    public boolean containsKey(String key) {
        return props.containsKey(key);
    }
    
    /**
     * 获取属性表中键值对数量
     * @return
     */
    public int size() {
        return props.size();
    }

    /**
     * 检查属性表是否为空
     * @return
     */
    public boolean isEmpty() {
        return props.isEmpty();
    }

    /**
     * 清空属性表
     */
    public synchronized void clear() {
        props.clear();
        keyCommentMap.clear();
    }

    /**
     * 获取属性表中所有key的集合。
     * 
     * @return
     */
    public Set<String> propertyNames() {
        return props.stringPropertyNames();
    }


    public synchronized String toString() {
        StringBuffer buffer = new StringBuffer();
        Iterator<Map.Entry<String, String>> kvIter = keyCommentMap.entrySet().iterator();
        buffer.append("[");
        while(kvIter.hasNext()){
            buffer.append("{");
            Map.Entry<String, String> entry = kvIter.next();
            String key = entry.getKey();
            String val = getProperty(key);
            String comment = entry.getValue();
            buffer.append("key="+key+",value="+val+",comment="+comment);
            buffer.append("}");
        }
        buffer.append("]");
        return buffer.toString();
    }

    public boolean equals(Object o) {
        //不考虑注释说明是否相同
        return props.equals(o);
    }

    public int hashCode() {
        return props.hashCode();
    }
    
    private void load0(LineReader lr) throws IOException {
        char[] convtBuf = new char[1024];
        int limit;
        int keyLen;
        int valueStart;
        char c;
        boolean hasSep;
        boolean precedingBackslash;
        StringBuffer buffer = new StringBuffer();

        while ((limit = lr.readLine()) >= 0) {
            c = 0;
            keyLen = 0;
            valueStart = limit;
            hasSep = false;
            //获取注释
            c = lr.lineBuf[keyLen];
            if(c == '#' || c == '!'){
                String comment = loadConvert(lr.lineBuf, 1, limit - 1, convtBuf);
                if(buffer.length() > 0){
                    buffer.append("
");
                }
                buffer.append(comment);
                continue;
            }
            precedingBackslash = false;
            while (keyLen < limit) {
                c = lr.lineBuf[keyLen];
                //need check if escaped.
                if ((c == '=' ||  c == ':') && !precedingBackslash) {
                    valueStart = keyLen + 1;
                    hasSep = true;
                    break;
                } else if ((c == ' ' || c == '	' ||  c == 'f') && !precedingBackslash) {
                    valueStart = keyLen + 1;
                    break;
                } 
                if (c == '\') {
                    precedingBackslash = !precedingBackslash;
                } else {
                    precedingBackslash = false;
                }
                keyLen++;
            }
            while (valueStart < limit) {
                c = lr.lineBuf[valueStart];
                if (c != ' ' && c != '	' &&  c != 'f') {
                    if (!hasSep && (c == '=' ||  c == ':')) {
                        hasSep = true;
                    } else {
                        break;
                    }
                }
                valueStart++;
            }
            String key = loadConvert(lr.lineBuf, 0, keyLen, convtBuf);
            String value = loadConvert(lr.lineBuf, valueStart, limit - valueStart, convtBuf);
            setProperty(key, value, buffer.toString());
            //reset buffer
            buffer = new StringBuffer();
        }
    }

    /* 
     * 基于java.util.Properties.LineReader进行改造
     * 
     * Read in a "logical line" from an InputStream/Reader, skip all comment
     * and blank lines and filter out those leading whitespace characters 
     * (u0020, u0009 and u000c) from the beginning of a "natural line". 
     * Method returns the char length of the "logical line" and stores 
     * the line in "lineBuf". 
     */
    class LineReader {
        public LineReader(InputStream inStream) {
            this.inStream = inStream;
            inByteBuf = new byte[8192]; 
        }

        public LineReader(Reader reader) {
            this.reader = reader;
            inCharBuf = new char[8192]; 
        }

        byte[] inByteBuf;
        char[] inCharBuf;
        char[] lineBuf = new char[1024];
        int inLimit = 0;
        int inOff = 0;
        InputStream inStream;
        Reader reader;

        int readLine() throws IOException {
            int len = 0;
            char c = 0;

            boolean skipWhiteSpace = true;
            boolean isNewLine = true;
            boolean appendedLineBegin = false;
            boolean precedingBackslash = false;
            boolean skipLF = false;

            while (true) {
                if (inOff >= inLimit) {
                    inLimit = (inStream==null)?reader.read(inCharBuf)
                            :inStream.read(inByteBuf);
                    inOff = 0;
                    if (inLimit <= 0) {
                        if (len == 0) { 
                            return -1; 
                        }
                        return len;
                    }
                }     
                if (inStream != null) {
                    //The line below is equivalent to calling a 
                    //ISO8859-1 decoder.
                    c = (char) (0xff & inByteBuf[inOff++]);
                } else {
                    c = inCharBuf[inOff++];
                }
                if (skipLF) {
                    skipLF = false;
                    if (c == '
') {
                        continue;
                    }
                }
                if (skipWhiteSpace) {
                    if (c == ' ' || c == '	' || c == 'f') {
                        continue;
                    }
                    if (!appendedLineBegin && (c == '
' || c == '
')) {
                        continue;
                    }
                    skipWhiteSpace = false;
                    appendedLineBegin = false;
                }
                if (isNewLine) {
                    isNewLine = false;
                }

                if (c != '
' && c != '
') {
                    lineBuf[len++] = c;
                    if (len == lineBuf.length) {
                        int newLength = lineBuf.length * 2;
                        if (newLength < 0) {
                            newLength = Integer.MAX_VALUE;
                        }
                        char[] buf = new char[newLength];
                        System.arraycopy(lineBuf, 0, buf, 0, lineBuf.length);
                        lineBuf = buf;
                    }
                    //flip the preceding backslash flag
                    if (c == '\') {
                        precedingBackslash = !precedingBackslash;
                    } else {
                        precedingBackslash = false;
                    }
                }
                else {
                    // reached EOL
                    if (len == 0) {
                        isNewLine = true;
                        skipWhiteSpace = true;
                        len = 0;
                        continue;
                    }
                    if (inOff >= inLimit) {
                        inLimit = (inStream==null)
                                ?reader.read(inCharBuf)
                                        :inStream.read(inByteBuf);
                                inOff = 0;
                                if (inLimit <= 0) {
                                    return len;
                                }
                    }
                    if (precedingBackslash) {
                        len -= 1;
                        //skip the leading whitespace characters in following line
                        skipWhiteSpace = true;
                        appendedLineBegin = true;
                        precedingBackslash = false;
                        if (c == '
') {
                            skipLF = true;
                        }
                    } else {
                        return len;
                    }
                }
            }
        }
    }

    /*
     * Converts encoded &#92;uxxxx to unicode chars
     * and changes special saved chars to their original forms
     */
    private String loadConvert (char[] in, int off, int len, char[] convtBuf) {
        if (convtBuf.length < len) {
            int newLen = len * 2;
            if (newLen < 0) {
                newLen = Integer.MAX_VALUE;
            } 
            convtBuf = new char[newLen];
        }
        char aChar;
        char[] out = convtBuf; 
        int outLen = 0;
        int end = off + len;

        while (off < end) {
            aChar = in[off++];
            if (aChar == '\') {
                aChar = in[off++];   
                if(aChar == 'u') {
                    // Read the xxxx
                    int value=0;
                    for (int i=0; i<4; i++) {
                        aChar = in[off++];  
                        switch (aChar) {
                        case '0': case '1': case '2': case '3': case '4':
                        case '5': case '6': case '7': case '8': case '9':
                            value = (value << 4) + aChar - '0';
                            break;
                        case 'a': case 'b': case 'c':
                        case 'd': case 'e': case 'f':
                            value = (value << 4) + 10 + aChar - 'a';
                            break;
                        case 'A': case 'B': case 'C':
                        case 'D': case 'E': case 'F':
                            value = (value << 4) + 10 + aChar - 'A';
                            break;
                        default:
                            throw new IllegalArgumentException(
                                    "Malformed \uxxxx encoding.");
                        }
                    }
                    out[outLen++] = (char)value;
                } else {
                    if (aChar == 't') aChar = '	'; 
                    else if (aChar == 'r') aChar = '
';
                    else if (aChar == 'n') aChar = '
';
                    else if (aChar == 'f') aChar = 'f'; 
                    out[outLen++] = aChar;
                }
            } else {
                out[outLen++] = (char)aChar;
            }
        }
        return new String (out, 0, outLen);
    }

    private void store0(BufferedWriter bw, boolean escUnicode)
            throws IOException{
        synchronized (this) {
            Iterator<Map.Entry<String, String>> kvIter = keyCommentMap.entrySet().iterator();
            while(kvIter.hasNext()){
                Map.Entry<String, String> entry = kvIter.next();
                String key = entry.getKey();
                String val = getProperty(key);
                String comment = entry.getValue();
                key = saveConvert(key, true, escUnicode);
                /* No need to escape embedded and trailing spaces for value, hence
                 * pass false to flag.
                 */
                val = saveConvert(val, false, escUnicode);
                if(!comment.equals(BLANK))
                    writeComments(bw, comment);
                bw.write(key + "=" + val);
                bw.newLine();
            }
        }
        bw.flush();
    }

    private static void writeComments(BufferedWriter bw, String comments) 
            throws IOException {
        bw.write("#");
        int len = comments.length();  
        int current = 0;
        int last = 0;
        while (current < len) {
            char c = comments.charAt(current);
            if (c > 'u00ff' || c == '
' || c == '
') {
                if (last != current) 
                    bw.write(comments.substring(last, current));
                if (c > 'u00ff') {
                    bw.write(c);
                } else {
                    bw.newLine();
                    if (c == '
' && 
                            current != len - 1 && 
                            comments.charAt(current + 1) == '
') {
                        current++;
                    }
                    if (current == len - 1 ||
                            (comments.charAt(current + 1) != '#' &&
                            comments.charAt(current + 1) != '!'))
                        bw.write("#");
                }
                last = current + 1;
            } 
            current++;
        }
        if (last != current) 
            bw.write(comments.substring(last, current));
        bw.newLine();
    }

    /*
     * Converts unicodes to encoded &#92;uxxxx and escapes
     * special characters with a preceding slash
     */
    private String saveConvert(String theString,
            boolean escapeSpace,
            boolean escapeUnicode) {
        int len = theString.length();
        int bufLen = len * 2;
        if (bufLen < 0) {
            bufLen = Integer.MAX_VALUE;
        }
        StringBuffer outBuffer = new StringBuffer(bufLen);

        for(int x=0; x<len; x++) {
            char aChar = theString.charAt(x);
            // Handle common case first, selecting largest block that
            // avoids the specials below
            if ((aChar > 61) && (aChar < 127)) {
                if (aChar == '\') {
                    outBuffer.append('\'); outBuffer.append('\');
                    continue;
                }
                outBuffer.append(aChar);
                continue;
            }
            switch(aChar) {
            case ' ':
                if (x == 0 || escapeSpace) 
                    outBuffer.append('\');
                outBuffer.append(' ');
                break;
            case '	':outBuffer.append('\'); outBuffer.append('t');
            break;
            case '
':outBuffer.append('\'); outBuffer.append('n');
            break;
            case '
':outBuffer.append('\'); outBuffer.append('r');
            break;
            case 'f':outBuffer.append('\'); outBuffer.append('f');
            break;
            case '=': // Fall through
            case ':': // Fall through
            case '#': // Fall through
            case '!':
                outBuffer.append('\'); outBuffer.append(aChar);
                break;
            default:
                if (((aChar < 0x0020) || (aChar > 0x007e)) & escapeUnicode ) {
                    outBuffer.append('\');
                    outBuffer.append('u');
                    outBuffer.append(toHex((aChar >> 12) & 0xF));
                    outBuffer.append(toHex((aChar >>  8) & 0xF));
                    outBuffer.append(toHex((aChar >>  4) & 0xF));
                    outBuffer.append(toHex( aChar        & 0xF));
                } else {
                    outBuffer.append(aChar);
                }
            }
        }
        return outBuffer.toString();
    }

    /**
     * Convert a nibble to a hex character
     * @param    nibble    the nibble to convert.
     */
    private static char toHex(int nibble) {
        return hexDigit[(nibble & 0xF)];
    }

    /** A table of hex digits */
    private static final char[] hexDigit = {
        '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
    };

}