javaIO流07：处理流BufferedReader和BufferedWriter，Buffer拷贝

BufferedReader

BufferedReader（处理流）：从字符输入流中读取文本，缓冲各个字符，从而实现字符、数组和行的高效读取。

1. BufferedReader的方法

2. BufferedReader用法示例

public class Demo9 {
    //读取一个字符文件
    public static void main(String[] args) throws IOException {
        String filePath="D:/IOFile/news5.txt";
        //创建BufferedReader，传一个FileReader对象
        BufferedReader bufferedReader = new BufferedReader(new FileReader(filePath));
        String line;
        //调用readline方法按行读取，效率高
        //如果已到达流末尾，则返回 null 表示文件读取完毕
         while ((line=bufferedReader.readLine())!=null){
             System.out.println(line);
         }
         //关闭流，只需要关闭BufferedReader，虽然我们创建了节点流，
        // 但是当我们关闭BufferedReader时，底层会调用我们传进来的节点流对象的close，从而关闭节点流
         bufferedReader.close();
    }
}

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BufferedWriter

将文本写入字符输出流，缓冲各个字符，从而提供单个字符、数组和字符串的高效写入。

1. BufferedWriter的方法

2. BufferedWriter用法示例

public class Demo10 {
    public static void main(String[] args) throws IOException {
        String filePath="D:/IOFile/news7.txt";
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(filePath));
        bufferedWriter.write("hello,");
        bufferedWriter.write("world");
        //换行
        bufferedWriter.newLine();
        bufferedWriter.write("hello,");
        bufferedWriter.newLine();
        bufferedWriter.write("world");
        //追加写入
        BufferedWriter bufferedWriter2 = new BufferedWriter(new FileWriter(filePath,true));
        bufferedWriter2.write(123);
    }
}
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BufferedReader和BufferedWriter拷贝

使用BufferedReader将需要拷贝的文件读取到程序，再使用BufferedWriter写入到指定的位置

public class Demo11 {
    public static void main(String[] args) {
        //Reader和Writer都是读取字符的，不能读取二进制文件（图片，视频，音频。。）
        String fileReaderPath="D:/IOFile/news7.txt";
        String fileWritePath="D:/IOFile/news/news7.txt";
        BufferedReader bufferedReader=null;
        BufferedWriter bufferedWriter=null;
        String line;
        try {
             bufferedReader = new BufferedReader(new FileReader(fileReaderPath));
             bufferedWriter = new BufferedWriter(new FileWriter(fileWritePath));

            while ((line=bufferedReader.readLine())!=null){
                //readLine是一行一行的进行读取但是读取之后是不会自动换行的，所以我们需要调用newLine
                bufferedWriter.write(line);
                bufferedWriter.newLine();

            }
            System.out.println("字符文件拷贝成功");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedReader!=null){
                    bufferedReader.close();
                }
                if (bufferedWriter!=null){
                    bufferedWriter.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}

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