字节流简单文件复制

@Test
public void FileInput() throws IOException {
    File file = new File("a.txt");　　　　//源，可用路径地址代替 文件格式任意
    FileInputStream fileInputStream = new FileInputStream(file);
    FileOutputStream fileOutputStream = new FileOutputStream("b.txt");　　　　//复制后文件保存地址，默认在工程目录下
    byte[] bytes= new byte[1024];　　　　//缓冲容器
    int len;
    while ((len = fileInputStream.read(bytes))!=-1){
        fileOutputStream.write(bytes,0,len);
    }
    fileInputStream.close();
    fileOutputStream.close();
}