我在Java中有此方法，并且我想对其进行改进。
该方法用于用新字节替换某些文件的某些部分（在开头，中间或结尾）（所选部分可以用更少或更多的字节替换）。
通过位置（start）和quantity完成选择。
我不能使用外部库（guava或其他库）。
这是我的旧代码：
public static void replaceBytesFile(RandomaccessFile rafTarget,byte[] replacers,int start,int quantity) {
//replaces exact amount of bytes of a file starting at a specified position
RandomaccessFile rafTemp = null;
//Ini Select a Random NonExistent File
File userDirectory = new File(System.getProperty("user.dir"));
File temporalFile;
boolean existsTemporalFile = false;
String temporalFilename = "";
while (!existsTemporalFile) {
temporalFilename = "File_" + Double.toString(100000 * Math.random()) + ".tmp";
temporalFilename = userDirectory + MethodGen.FS + temporalFilename;
temporalFile = new File(temporalFilename);
if (!temporalFile.exists()) {
existsTemporalFile = true;
}
}
//End Select a Random NonExistent File
try {
rafTemp = new RandomaccessFile(temporalFilename,"rw");
int workBufferSize = 65536;
//Ini Copy first (Start - 1) MethodBytes
int step = workBufferSize;
int countPosition = 0;
while (countPosition < start) {
rafTarget.seek(countPosition);
rafTemp.seek(countPosition);
if ((start - countPosition) < step) {
step = start - countPosition;
}
byte[] WorkBuffer = new byte[step];
rafTarget.read(WorkBuffer);
rafTemp.write(WorkBuffer);
countPosition += step;
}
//End Copy first (start - 1) MethodBytes
rafTemp.write(replacers);
rafTarget.seek(start + quantity);
int end = (int) rafTarget.length();
//Ini Copy last MethodBytes
step = workBufferSize;
countPosition = start + quantity;
while (countPosition < end) {
rafTarget.seek(countPosition);
rafTemp.seek(countPosition - quantity + replacers.length);
if ((end - countPosition) <= step) {
step = end - countPosition;
}
byte[] WorkBuffer = new byte[step];
rafTarget.read(WorkBuffer);
rafTemp.write(WorkBuffer);
countPosition += step;
}
//End Copy last MethodBytes
rafTarget.setLength(0);
step = workBufferSize;
countPosition = 0;
end = (int) rafTemp.length();
//Ini Copy all MethodBytes to original
while (countPosition < end) {
rafTemp.seek(countPosition);
rafTarget.seek(countPosition);
if ((end - countPosition) <= step) {
step = end - countPosition;
}
byte[] WorkBuffer = new byte[step];
rafTemp.read(WorkBuffer);
rafTarget.write(WorkBuffer);
countPosition += step;
}
//End Copy all MethodBytes to original
rafTemp.close();
temporalFile = new File(temporalFilename);
temporalFile.delete();
} catch (IOException ioe) {
System.out.println(ioe.toString());
} finally {
try {
if (rafTemp != null) {
rafTemp.close();
}
} catch (IOException e) {
}
}
}
我要手动将其从原始文件复制到执行更改的临时文件中，
我的代码正在运行，但是我想知道Java 8中的一些最佳替代方法（首选）。
现在测试如何？
public static void main(String[] args) {
String originalFilename = "OriginalTraveling.txt";
String copiedFilename = "TravelingToBeChanged.txt";
Path copiedPath = Paths.get(copiedFilename);
Path originalPath = new File(originalFilename).toPath();
System.out.println("filename:" + originalFilename);
String contet = "I want to travel to my Country.";
try {
RandomaccessFile raf = new RandomaccessFile(originalFilename,"rw");
putBytesFile(raf,contet.getBytes(),0);
Files.copy(originalPath,copiedPath,StandardCopyOption.REPLACE_EXISTING);
}
catch (IOException e) {
System.out.println("Exception caught " + e.toString());
}
try {
RandomaccessFile raf = new RandomaccessFile(copiedFilename,"rw");
String toBeChanged = "my Country.";
String toBeInserted = "India,China,Europe,Latin America,Australia.";
int position = contet.indexOf(toBeChanged);
replaceBytesFile(raf,toBeInserted.getBytes(),position,toBeChanged.length());
}
catch (IOException e) {
System.out.println("Exception caught " + e.toString());
}
try {
RandomaccessFile raf = new RandomaccessFile(copiedFilename,"rw");
String replacedContent = new String(getBytesFile(raf,(int) raf.length()));
String toBeChanged = "Latin America";
String toBeInserted = "Colombia";
int position = replacedContent.indexOf(toBeChanged);
replaceBytesFile(raf,toBeChanged.length());
} catch (IOException e) {
System.out.println("Exception caught " + e.toString());
}
}
放置字节的方法！
public static void putBytesFile(RandomaccessFile RAFTarget,byte[] content,int position) {
int size = content.length;
try {
long oldPosition = RAFTarget.getFilePointer();
if (!((position < 0) || !(size > 0))) {
RAFTarget.seek(position);
RAFTarget.write(content);
RAFTarget.seek(oldPosition);
}
} catch (java.io.IOException e) {
System.out.println(e.toString());
}
}
方法获取文件！
public static byte[] getBytesFile(RandomaccessFile RAFSource,int position,int quantity) {
byte[] content = null;
try {
long oldPosition = RAFSource.getFilePointer();
if ((position < 0) || !(quantity > 0)) {
return (content);
} else {
if (RAFSource.length() < (position + quantity)) {
quantity = (int) RAFSource.length() - position;
}
RAFSource.seek(position);
content = new byte[quantity];
RAFSource.read(content);
RAFSource.seek(oldPosition);
}
} catch (java.io.IOException e) {
System.out.println(e.toString());
}
return content;
}
OriginalTraveling.txt
的内容I want to travel to my Country.
TravelingToBeChanged.txt
的内容I want to travel to India,Australia.
最后， TravelingToBeChanged.txt
的内容I want to travel to India,Colombia,Australia.
如果可以注意到，它们不会更改相同的字节数。
您知道一些替代文件内容的替代方法吗？