NIO学习总结
/** * 使用传统的I/O读取文件内容* @param filePath文件路径 * @throws IOException*/ public static void ioRead(String filePath) throws IOException { File file = new File(filePath); FileInputStream fis = new FileInputStream(file); byte[] b = new byte; fis.read(b); System.out.println(new String(b)); }/*** 使用NIO读取文件内容* @param filePath 文件路径* @throws IOException*/public static void nioRead(String filePath) throws IOException { File file = new File(filePath); FileInputStream fis = new FileInputStream(file); FileChannel channel = fis.getChannel(); ByteBuffer b = ByteBuffer.allocate(1024); channel.read(b); byte[] by = b.array(); System.out.println(new String(by));}/*** 传统I/O写文件* * @param filePath文件路径* @throws IOException*/public static void ioWrite(String filePath) throws IOException { File file = new File(filePath); FileOutputStream fos = new FileOutputStream(file); String[] contents = new String[] { "qian", "hao" }; for (String content : contents) { byte[] b = content.getBytes(Charset.forName("UTF-8")); fos.write(b); } }/*** NIO写文件* @param filePath 文件路径* @throws IOException*/ public static void nioWrite(String filePath) throws IOException { File file = new File(filePath); FileOutputStream fos = new FileOutputStream(file); // 获取文件通道 FileChannel channel = fos.getChannel(); // 设置文件缓冲区 ByteBuffer buffer = ByteBuffer.allocate(1024); String[] contents = new String[] { "qian", "hao" }; // 将数据读入缓冲区中 for (String content : contents) {buffer.put(content.getBytes()); } // 通道反转(将读通道转化为写通道)buffer.flip(); // 将文件写入写通道中channel.write(buffer); }/*** 将一个文件内容复制到另外一个文件中* @param resource源文件路径* @param destination 目标文件路径* @throws IOException*/ public static void nioCopyFile(String resource, String destination)throws IOException { // 设置文件输入流 FileInputStream fis = new FileInputStream(resource); // 设置文件输出流 FileOutputStream fos = new FileOutputStream(destination); // 设置输入通道 FileChannel readChannel = fis.getChannel(); // 设置输出通道 FileChannel writeChannel = fos.getChannel(); // 创建缓冲区 ByteBuffer buffer = ByteBuffer.allocate(1024); // 复制文件 while (true) { // 清空缓冲，使其接受新的数据buffer.clear(); // 从输入通道中将数据写入缓冲区中int len = readChannel.read(buffer); // 判断是否文件已读取完成if (len == -1) { break;} // 将缓冲区的数据些到另外一个通道，(输入通道反转到输出通道) buffer.flip(); // 从输出通道将数据写到缓冲区,写入文件中 writeChannel.write(buffer);} }
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