byte 读写文件

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;public class FileHelper {
//第一种获取文件内容方式
public byte[] getContent(String filePath) throws IOException {
File file = new File(filePath);long fileSize = file.length();
if (fileSize > Integer.MAX_VALUE) {
System.out.println("file too big...");
return null;
}FileInputStream fi = new FileInputStream(file);byte[] buffer = new byte[(int) fileSize];int offset = 0;int numRead = 0;while (offset < buffer.length&& (numRead = fi.read(buffer, offset, buffer.length - offset)) >= 0) {offset += numRead;}// 确保所有数据均被读取if (offset != buffer.length) {throw new IOException("Could not completely read file "
+ file.getName());}fi.close();return buffer;
}//第二种获取文件内容方式
public byte[] getContent2(String filePath) throws IOException
{
FileInputStream in=new FileInputStream(filePath);ByteArrayOutputStream out=new ByteArrayOutputStream(1024);System.out.println("bytes available:"+in.available());byte[] temp=new byte[1024];int size=0;while((size=in.read(temp))!=-1)
{
out.write(temp,0,size);
}in.close();byte[] bytes=out.toByteArray();
System.out.println("bytes size got is:"+bytes.length);return bytes;
}
        //将byte数组写入文件
public void createFile(String path, byte[] content) throws IOException {FileOutputStream fos = new FileOutputStream(path);fos.write(content);
fos.close();
}}