转换流

package file;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

/*
 转换流：
 
 输入字节流的转换流： 
     InputStreamReader是字节流通向字符流的桥梁     
 输出字节流的转换流： 
     OutputStreamWriter是字节流通向字符流的桥梁     
         
  转换流的作用：
     字节流---->字符流
     
 
 */
public class Demo12 {
    public static void main(String[] args) throws IOException {
//        readTest();
//        writeTest();
//        writeTest2();
        readTest2();
    }
    
    //使用输入字节流的转换流 指定码表读取数据
    public static void readTest2() throws IOException {
        File file = new File("F:\a.txt");
        //建立数据输入通道
        FileInputStream fileInputStream = new FileInputStream(file);
        //把输入字节流转换 并且指定码表
        InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream,"utf-8");
        char[] buf = new char[1024];
        int length = 0;
        while((length = inputStreamReader.read(buf))!=-1)  {
            System.out.println(new String(buf,0,length));
        }
        inputStreamReader.close();
    }
    
    
    //使用输出字节流的转换流 指定码表写出数据
    public static void writeTest2() throws IOException {
        File file = new File("F:\a.txt");
        //建立数据输出通道
        FileOutputStream fileOutputStream = new FileOutputStream(file);
        //把输出字节流转换成字符流并且指定码表
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, "utf-8");
        outputStreamWriter.write("ab哈哈哈");
        //关闭资源
        outputStreamWriter.close();
        
    }
    
    // 输出字节流的转换流： 
    public static void writeTest() throws IOException {
        File file = new File("F:\a.txt");
        FileOutputStream fileOutputStream = new FileOutputStream(file);
        //输出字节流转换成字符流
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream);
        
        outputStreamWriter.write("hello大家好");
        outputStreamWriter.close();
    }
    
    
    // 输入字节流的转换流： 字节流---->字符流
    public static void readTest() throws IOException {
        InputStream in = System.in;
        //需要把字节流转换成字符流
        InputStreamReader inputStreamReader = new InputStreamReader(in);
        //使用字符流的缓冲类
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
        
        String line = null;
        while((line = bufferedReader.readLine())!= null) {
            System.out.println("内容：" + line);
        }
        bufferedReader.close();
    }
}