转换流，可以将一个字节流转换为字符流，也可以将一个字符流转换为字节流

• OutputStreamWriter：将输出的字符流转换为字节流的输出形式
• InputStreamReader：将输入的字节流转换为字符流

示例

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;

public class ChangerStreamDemo {

    public static void main(String[] args) throws FileNotFoundException {
        //InputStream in=new FileInputStream("/Users/a10.11.5/test/123.txt");
        //read(in);
        OutputStream out =new FileOutputStream("/Users/a10.11.5/test/123.txt",true);
        writer(out);
    }
//InputStreamReader：将输入的字节流转换为字符流
    public static void read(InputStream in){
        Reader reader=new InputStreamReader(in);
        char [] cs=new char[1024];
        int len=-1;
        try {
            while((len=reader.read(cs))!=-1) {
                System.out.println(new String(cs,0,len));
            }
            reader.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
//OutputStreamWriter：将输出的字符流转换为字节流的输出形式
    public static void writer(OutputStream out){
        Writer writer=new OutputStreamWriter(out);
        try {
            writer.write("，开开心心来玩耍\r\n");
            writer.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}