import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
public class InsertContent {
public static void insert(String fileName,long pos,String insertContent) throws IOException{
File file = File.createTempFile("tmp",null);
file.deleteOnExit();
RandomAccessFile raf = new RandomAccessFile(fileName,"rw");
FileInputStream fileInputStream = new FileInputStream(file);
FileOutputStream fileOutputStream = new FileOutputStream(file);
raf.seek(pos);
byte[] buff = new byte[64];
int hasRead = 0;
while((hasRead = raf.read(buff)) > 0){
fileOutputStream.write(buff);
}
raf.seek(pos);
raf.write(insertContent.getBytes());
//追加文件插入点之后的内容
while((hasRead = fileInputStream.read(buff)) > 0){
raf.write(buff,hasRead);
}
raf.close();
fileInputStream.close();
fileOutputStream.close();
}
public static void main(String[] args) throws IOException {
insert("F:AttendanceActivity.java",57,"插入的内容rn");
}
}
