一、开发过程中遇到问题：
（1）文件内容只能等长替换，如果文件内容少了就会乱行。
解决办法：我主要是进行xml文件内容解析的，用添加随机字符串的方式进行了解决，这样既不影响文件内容解析，也把问题解决了。
二、代码：
public class FileUtils {
/**
* 读写文件内容
* @param filePath
*/
public static void readWriteFile(String filePath) {
RandomAccessFile raf = null;
try {
raf = new RandomAccessFile(filePath, "rw");
String line = null;
long lastPoint = 0;
int length=0;
while ((line = raf.readLine()) != null) {
String str = verifyXML(line);
long ponit = raf.getFilePointer();
length=line.length()-str.length();
str=getRandomChar(length,str);
raf.seek(lastPoint);
raf.writeBytes(str);
lastPoint = ponit;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
raf.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 乱码字符去除
* @param in
* @return
*/
public static String verifyXML(String in) {
StringBuffer out = new StringBuffer();
char current;
if (in == null || ("".equals(in)))
return "";
for (int i = 0; i < in.length(); i++) {
current = in.charAt(i);
if ((current==0x9)||(current==0xA)||(current==0xD)
||((current>=0x20)&&(current<=0xD7FF))
||((current>=0xE000)&&(current<=0xFFFD))
||((current>=0x10000)&&(current<=0x10FFFF))){
out.append(current);
}
}
return out.toString();
}
/**
* 生成指定长度随机字符串
* @param length
* @param str
* @return
*/
public static String getRandomChar(int length,String str) {
char[] chr = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
Random random = new Random();
StringBuffer sb = new StringBuffer(str);
for (int i = 0; i < length; i++) {
sb.append(chr[random.nextInt(62)]);
}
return sb.toString();
}
public static void main(String[] args) {
String filePath="D://test.xml";
readWriteFile(filePath);
}
}