Java IO InputStreamReader和OutputStreamWriter

InputStreamReader和OutputStreamWriter 是字节流通向字符流的桥梁：它使用指定的 charset 读写字节并将其解码为字符。
InputStreamReader 的作用是将“字节输入流”转换成“字符输入流”。它继承于Reader。
OutputStreamWriter 的作用是将“字符输出流”转换成“字节输出流”。它继承于Writer。

package com.louisgeek.appupdatetool;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;

/**
 * 转换流
 * Created by louisgeek on 2016/8/22.
 */
public class CharStreamAndByteStreamTest {

    public static void main(String[] args) throws Exception{
        //outputStreamWriter();
        inputStreamReader();
    }

    private static void outputStreamWriter() throws IOException {
        File file=new File("d:"+File.separator+"text.txt");

        Writer writer=new OutputStreamWriter(new FileOutputStream(file));
        writer.write("hello android");
        writer.close();
    }

    private static void inputStreamReader() throws IOException {
        File file=new File("d:"+File.separator+"text.txt");

        Reader reader=new InputStreamReader(new FileInputStream(file));

        char[] charArr=new char[1024];
        int len=reader.read(charArr);

        System.out.println(new String(charArr,0,len));

        reader.close();
    }
}