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();

	}

}