处理流_转换流（字符流）

处理流_转换流（字符流）

InputStreamReader:将InputStream转换为Reader,实现字节的输入流转换为字符的输入流

/**
 * 处理六：转换流的使用
 * 1.转换流：属于字符流
 *  InputStreamReader:将一个字节的输入流转换为字符的输入流
 *  OutputStreamWriter：将一个字符的输出流转换为字节的输出流
 *
 * 2.作用:提供字符与字节之间的转换
 * 3.解码：字节、数组 ---》 字符、字符串  InputStreamReader
 *   编码：字符、字符串 ---》 字节、数组  OutputStreamWriter
 *
 * 4.字符集
 */
public class IOStreamReaderAndWriter {
    public static void main(String[] args) {
        InputStreamReader inputStreamReader = null;
        try {
            FileInputStream fileInputStream = new FileInputStream("基础语法\a.txt");
//        InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream);//使用系默认的字符集  UTF-8
            //使用utf-8  取决于原来保存时的字符集
            inputStreamReader = new InputStreamReader(fileInputStream,"UTF-8");
            char[] cbuf = new char[20];
            int len;
            while ((len = inputStreamReader.read(cbuf)) != -1){
                String string = new String(cbuf,0,len);
                System.out.println(string);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (inputStreamReader != null)
                inputStreamReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

OutputStreamWriter:将Writer转换为OutputStream

/**
 * 处理六：转换流的使用
 * 1.转换流：属于字符流
 *  InputStreamReader:将一个字节的输入流转换为字符的输入流
 *  OutputStreamWriter：将一个字符的输出流转换为字节的输出流
 *
 * 2.作用:提供字符与字节之间的转换
 * 3.解码：字节、数组 ---》 字符、字符串  InputStreamReader
 *   编码：字符、字符串 ---》 字节、数组  OutputStreamWriter
 *
 * 4.字符集
 * 
 */
public class IOStreamReaderAndWriter {
    public static void main(String[] args) {
        InputStreamReader inputStreamReader = null;
        OutputStreamWriter outputStreamWriter = null;
        try {
        /*
        综合使用InputStreamReader和OutputStreamWriter  实现文本文件字符集的转换
         */
            //造文件 、造流
            File file1 = new File("基础语法\a.txt");
            File file2 = new File("基础语法\gbk_a.txt");

            FileInputStream fileInputStream = new FileInputStream(file1);
            FileOutputStream fileOutputStream = new FileOutputStream(file2);

            inputStreamReader = new InputStreamReader(fileInputStream,"utf-8");
            outputStreamWriter = new OutputStreamWriter(fileOutputStream,"gbk");

            //读写过程
            char[] cbuf = new char[20];
            int len;
            while ((len = inputStreamReader.read(cbuf)) != -1){
                outputStreamWriter.write(cbuf,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭资源
            try {
                if (inputStreamReader != null)
                inputStreamReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (outputStreamWriter != null)
                outputStreamWriter.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}