Java IO流--使用缓冲流实现非文本文件和文本文件的复制

BufferedInputStream
BufferedOutputStream
BufferedReader
BufferedWriter

@Test
    public void test1() {
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            //1.造文件
            File file = new File("工作二维码.png");
            File file1 = new File("工作二维码2.png");
            //2.造流
            //2.1造节点流
            FileInputStream fis = new FileInputStream(file);
            FileOutputStream fos = new FileOutputStream(file1);
            //2.2造缓冲流
            bis = new BufferedInputStream(fis);
            bos = new BufferedOutputStream(fos);
            //3.复制的细节：读取，写入
            byte[] buffer = new byte[5];
            int len;
            while ((len = bis.read(buffer)) != -1) {
                bos.write(buffer, 0, len);
            }
        } catch (Exception e) {
                e.printStackTrace();
        } finally {
            //4.关闭资源
            //要求：先关闭外层的流，再关闭内层的流
            //在关闭外层流的同时，内层的流也会自动关闭，所以关于内层流的关闭，我们可以省略。
            if (bis !=null){
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bos!=null){
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

/**
 * 演示BufferedWriter的使用
 */
public class BufferedWriter_ {
    public static void main(String[] args) {
        String filePath = "D:\\ok.txt";
        BufferedWriter bufferedWriter = null;
        try {
            //1.new FileWriter(filePath,true) 表示以追加的方式写入
            //2.new FileWriter(filePath) 表示以覆盖的方式写入
            bufferedWriter = new BufferedWriter(new FileWriter(filePath));
            bufferedWriter.write("hello,北京！");
            bufferedWriter.newLine(); //插入一个和系统相关的换行符
            bufferedWriter.write("hello1,北京！");
            bufferedWriter.newLine(); //插入一个和系统相关的换行符
            bufferedWriter.write("hello2,北京！");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedWriter != null) {
                    bufferedWriter.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

/**
 * 演示BufferedReader的使用
 */
public class BufferedReader_ {
    public static void main(String[] args) {
        String filePath = "D:\\story.txt";
        //创建BufferedReader
        BufferedReader bufferedReader = null;
        try {
            bufferedReader = new BufferedReader(new FileReader(filePath));
            //读取
            String line; //按行读取,效率高
            //说明
            //1.bufferedReader.readLine() 是按行读取文件
            //2.当返回null时，表示文件读取完毕
            while ((line = bufferedReader.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedReader != null) {
                    //关闭流，这里注意，只需要关闭BufferedReader，因为底层会自动去关闭节点流FileReader。
                    /**
                     * public void close() throws IOException {
                     *         synchronized (lock) {
                     *             if (in == null)
                     *                 return;
                     *             try {
                     *                 in.close();//in 就是我们传入的 new FileReader(filePath)，关闭了。
                     *             } finally {
                     *                 in = null;
                     *                 cb = null;
                     *             }
                     *         }
                     *     }
                     */
                    bufferedReader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

@Test
    public void testBufferedReaderBufferedWriter() {
        BufferedReader bufferedReader = null;
        BufferedWriter bufferedWriter = null;
        try {
            //创建文件和相应的缓冲流
            bufferedReader = new BufferedReader(new FileReader(new File("学习记录.txt")));
            bufferedWriter = new BufferedWriter(new FileWriter(new File("学习记录4.txt")));
            //复制文件：读取和写入
            //方式一：使用char[]数组
//            char[] chars = new char[1024];
//            int len;
//            while ((len = bufferedReader.read(chars)) != -1) {
//                bufferedWriter.write(chars, 0, len);
//            }
            //方式二：使用String
            String data;
            while ((data=bufferedReader.readLine())!=null){
//                bufferedWriter.write(data+"\n");
                bufferedWriter.write(data);//data中不包含换行符
                bufferedWriter.newLine();//提供换行的操作
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭资源
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferedWriter != null) {
                try {
                    bufferedWriter.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }