原文地址:http://blog.csdn.net/benbenxiongyuan/article/details/53006097
参考地址:http://www.iteye.com/topic/156474
Properties调用store方法保存时,会把文件中原来的注释给冲掉,而且顺序会发生错乱,网上查找解决方案时,有人遇到了相同的问题,并给出了解决方案。
如下:


import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Properties; /** * Properties调用store方法保存时,会把文件中原来的注释给冲掉,而且顺序会发生错乱, * 网上查找解决方案时,有人遇到了相同的问题,并给出了解决方案 * * 改进java.util.Properties文件读写类,在读取properties文件的时候把注释和顺序格式都记录下来,操作时候也把添加顺序记录了, * 同时提供addComment()方法,可以添加注释,这样,经过处理的properties的可读性就能继续保持下来了,实现了SafeProperties.java,代码如下: * @author Administrator * */ @SuppressWarnings("all") public class SafeProperties extends Properties { private static final long serialVersionUID = 5011694856722313621L; private static final String keyValueSeparators = "=: \t\r\n\f"; private static final String strictKeyValueSeparators = "=:"; private static final String specialSaveChars = "=: \t\r\n\f#!"; private static final String whiteSpaceChars = " \t\r\n\f"; private PropertiesContext context = new PropertiesContext(); public PropertiesContext getContext() { return context; } public synchronized void load(InputStream inStream) throws IOException { BufferedReader in; in = new BufferedReader(new InputStreamReader(inStream, "8859_1")); while (true) { // Get next line String line = in.readLine(); // intract property/comment string String intactLine = line; if (line == null) return; if (line.length() > 0) { // Find start of key int len = line.length(); int keyStart; for (keyStart = 0; keyStart < len; keyStart++) if (whiteSpaceChars.indexOf(line.charAt(keyStart)) == -1) break; // Blank lines are ignored if (keyStart == len) continue; // Continue lines that end in slashes if they are not comments char firstChar = line.charAt(keyStart); if ((firstChar != '#') && (firstChar != '!')) { while (continueLine(line)) { String nextLine = in.readLine(); intactLine = intactLine + "\n" + nextLine; if (nextLine == null) nextLine = ""; String loppedLine = line.substring(0, len - 1); // Advance beyond whitespace on new line int startIndex; for (startIndex = 0; startIndex < nextLine.length(); startIndex++) if (whiteSpaceChars.indexOf(nextLine.charAt(startIndex)) == -1) break; nextLine = nextLine.substring(startIndex, nextLine.length()); line = new String(loppedLine + nextLine); len = line.length(); } // Find separation between key and value int separatorIndex; for (separatorIndex = keyStart; separatorIndex < len; separatorIndex++) { char currentChar = line.charAt(separatorIndex); if (currentChar == '\\') separatorIndex++; else if (keyValueSeparators.indexOf(currentChar) != -1) break; } // Skip over whitespace after key if any int valueIndex; for (valueIndex = separatorIndex; valueIndex < len; valueIndex++) if (whiteSpaceChars.indexOf(line.charAt(valueIndex)) == -1) break; // Skip over one non whitespace key value separators if any if (valueIndex < len) if (strictKeyValueSeparators.indexOf(line.charAt(valueIndex)) != -1) valueIndex++; // Skip over white space after other separators if any while (valueIndex < len) { if (whiteSpaceChars.indexOf(line.charAt(valueIndex)) == -1) break; valueIndex++; } String key = line.substring(keyStart, separatorIndex); String value = (separatorIndex < len) ? line.substring(valueIndex, len) : ""; // Convert then store key and value key = loadConvert(key); value = loadConvert(value); // memorize the property also with the whold string put(key, value, intactLine); } else { // memorize the comment string context.addCommentLine(intactLine); } } else { // memorize the string even the string is empty context.addCommentLine(intactLine); } } } /* * Converts encoded \uxxxx to unicode chars and changes special saved * chars to their original forms */ private String loadConvert(String theString) { char aChar; int len = theString.length(); StringBuffer outBuffer = new StringBuffer(len); for (int x = 0; x < len;) { aChar = theString.charAt(x++); if (aChar == '\\') { aChar = theString.charAt(x++); if (aChar == 'u') { // Read the xxxx int value = 0; for (int i = 0; i < 4; i++) { aChar = theString.charAt(x++); 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."); } } outBuffer.append((char) value); } else { if (aChar == 't') outBuffer.append('\t'); /* ibm@7211 */ else if (aChar == 'r') outBuffer.append('\r'); /* ibm@7211 */ else if (aChar == 'n') { /* * ibm@8897 do not convert a \n to a line.separator * because on some platforms line.separator is a String * of "\r\n". When a Properties class is saved as a file * (store()) and then restored (load()) the restored * input MUST be the same as the output (so that * Properties.equals() works). * */ outBuffer.append('\n'); /* ibm@8897 ibm@7211 */ } else if (aChar == 'f') outBuffer.append('\f'); /* ibm@7211 */ else /* ibm@7211 */ outBuffer.append(aChar); /* ibm@7211 */ } } else outBuffer.append(aChar); } return outBuffer.toString(); } public synchronized void store(OutputStream out, String header) throws IOException { BufferedWriter awriter; awriter = new BufferedWriter(new OutputStreamWriter(out, "8859_1")); if (header != null) writeln(awriter, "#" + header); List entrys = context.getCommentOrEntrys(); for (Iterator iter = entrys.iterator(); iter.hasNext();) { Object obj = iter.next(); if (obj.toString() != null) { writeln(awriter, obj.toString()); } } awriter.flush(); } private static void writeln(BufferedWriter bw, String s) throws IOException { bw.write(s); bw.newLine(); } private boolean continueLine(String line) { int slashCount = 0; int index = line.length() - 1; while ((index >= 0) && (line.charAt(index--) == '\\')) slashCount++; return (slashCount % 2 == 1); } /* * Converts unicodes to encoded \uxxxx and writes out any of the * characters in specialSaveChars with a preceding slash */ private String saveConvert(String theString, boolean escapeSpace) { int len = theString.length(); StringBuffer outBuffer = new StringBuffer(len * 2); for (int x = 0; x < len; x++) { char aChar = theString.charAt(x); switch (aChar) { case ' ': if (x == 0 || escapeSpace) outBuffer.append('\\'); outBuffer.append(' '); break; case '\\': outBuffer.append('\\'); outBuffer.append('\\'); break; case '\t': outBuffer.append('\\'); outBuffer.append('t'); break; case '\n': outBuffer.append('\\'); outBuffer.append('n'); break; case '\r': outBuffer.append('\\'); outBuffer.append('r'); break; case '\f': outBuffer.append('\\'); outBuffer.append('f'); break; default: if ((aChar < 0x0020) || (aChar > 0x007e)) { 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 { if (specialSaveChars.indexOf(aChar) != -1) outBuffer.append('\\'); 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' }; public synchronized Object put(Object key, Object value) { context.putOrUpdate(key.toString(), value.toString()); return super.put(key, value); } public synchronized Object put(Object key, Object value, String line) { context.putOrUpdate(key.toString(), value.toString(), line); return super.put(key, value); } public synchronized Object remove(Object key) { context.remove(key.toString()); return super.remove(key); } class PropertiesContext { private List commentOrEntrys = new ArrayList(); public List getCommentOrEntrys() { return commentOrEntrys; } public void addCommentLine(String line) { commentOrEntrys.add(line); } public void putOrUpdate(PropertyEntry pe) { remove(pe.getKey()); commentOrEntrys.add(pe); } public void putOrUpdate(String key, String value, String line) { PropertyEntry pe = new PropertyEntry(key, value, line); remove(key); commentOrEntrys.add(pe); } public void putOrUpdate(String key, String value) { PropertyEntry pe = new PropertyEntry(key, value); int index = remove(key); commentOrEntrys.add(index, pe); } public int remove(String key) { for (int index = 0; index < commentOrEntrys.size(); index++) { Object obj = commentOrEntrys.get(index); if (obj instanceof PropertyEntry) { if (obj != null) { if (key.equals(((PropertyEntry) obj).getKey())) { commentOrEntrys.remove(obj); return index; } } } } return commentOrEntrys.size(); } class PropertyEntry { private String key; private String value; private String line; public String getLine() { return line; } public void setLine(String line) { this.line = line; } public PropertyEntry(String key, String value) { this.key = key; this.value = value; } /** * @param key * @param value * @param line */ public PropertyEntry(String key, String value, String line) { this(key, value); this.line = line; } public String getKey() { return key; } public void setKey(String key) { this.key = key; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } public String toString() { if (line != null) { return line; } if (key != null && value != null) { String k = saveConvert(key, true); String v = saveConvert(value, false); return k + "=" + v; } return null; } } } /** * @param comment */ public void addComment(String comment) { if (comment != null) { context.addCommentLine("#" + comment); } } }