Java學習筆記39（轉換流）

轉換流：字元流和位元組流之間的橋梁

用於處理程式的編碼問題

OutputStreamWriter類：字元轉位元組流

寫文本文件：

package demo;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class Demo {
    public static void main(String[] args) throws IOException {
        writeGBK();
        writeUTF8();
    }

    public static void writeGBK() throws IOException {
        FileOutputStream fos = new FileOutputStream("d:\\gbk.txt");
        OutputStreamWriter osw = new OutputStreamWriter(fos, "GBK");
        osw.write("你好");// gbk的一個漢字是2個位元組
        osw.close();
    }

    public static void writeUTF8() throws IOException {
        FileOutputStream fos = new FileOutputStream("d:\\utf8.txt");
        OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");
        osw.write("你好");// utf8的一個漢字是3個位元組
        osw.close();
    }
}

InputStreamReader類：

位元組轉字元流過程：

這裡讀取上面寫的文本文件：

package demo;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class Demo {
    public static void main(String[] args) throws IOException {
        readGBK();
        readUTF8();
    }

    public static void readGBK() throws IOException {
        FileInputStream fis = new FileInputStream("d:\\gbk.txt");
        InputStreamReader isr = new InputStreamReader(fis);
        char[] ch = new char[1024];
        int len = isr.read(ch);
        System.out.println(new String(ch, 0, len));
    }

    public static void readUTF8() throws IOException {
        FileInputStream fis = new FileInputStream("d:\\utf8.txt");
        InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
        char[] ch = new char[1024];
        int len = isr.read(ch);
        System.out.println(new String(ch, 0, len));
    }
}

這裡註意，如果編碼集和讀取問文本不一致，就會發生亂碼或者輸出？的問題