JavaSE——IO流4：高级流(转换流InputStreamReader、OutputStreamWriter)

目录

一、转换流基本介绍 

二、转换流的使用

1.利用转换流按照指定字符编码读取 

2.利用转换流按照指定字符编码写出

3.将本地文件中的GBK文件，转成UTF-8

4.利用字节流读取文件中的数据，每次读一整行，而且不能出现乱码

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一、转换流基本介绍 

字符转换输入流：InputStreamReader        在Reader下

字符转换输出流：OutputStreamWriter        在Writer下

在JDK11中：

InputStreamReader被FileReader取代；

OutputStreamWriter被FileWriter取代

转换流的作用：

• 指定字符集读写数据(JDK11之后已经淘汰)
• 字节流想要使用字符流中的方法

二、转换流的使用

1.利用转换流按照指定字符编码读取 

public class ConvertStreamDemo1 {public static void main(String[] args) throws IOException { // 该方法在JDK11已过时/*InputStreamReader isr = new InputStreamReader(new FileInputStream("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfile.txt"),"GBK");int ch;while ((ch = isr.read()) != -1) {System.out.print((char) ch);}isr.close();*/// 使用下面的方法读取文件FileReader fr = new FileReader("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfile.txt",Charset.forName("GBK"));int ch;while ((ch = fr.read()) != -1) {System.out.print((char) ch);}fr.close();}
}

运行结果：

 

2.利用转换流按照指定字符编码写出

public class ConvertStreamDemo2 {public static void main(String[] args) throws IOException {// 下面的方式在JDK11已过时/*OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfiletest.txt"),"GBK");osw.write("万紫千红总是春");osw.close();*/FileWriter fw = new FileWriter("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfiletest1.txt",Charset.forName("GBK"));fw.write("万紫千红总是春");fw.close();}
}

3.将本地文件中的GBK文件，转成UTF-8

public class ConvertStreamDemo3 {public static void main(String[] args) throws IOException {/*InputStreamReader isr = new InputStreamReader(new FileInputStream("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfile.txt"), "GBK");OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("chapter18\\src\\com\\testdemo\\myconvertstream\\utf-8file.txt"), "UTF-8");int ch;while ((ch = isr.read()) != -1) {osw.write(ch);}osw.close();isr.close();*/FileReader fr = new FileReader("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfile.txt", Charset.forName("GBK"));FileWriter fw = new FileWriter("chapter18\\src\\com\\testdemo\\myconvertstream\\utf-8file1.txt", Charset.forName("UTF-8"));// 或者：// FileWriter fw = new FileWriter("chapter18\\src\\com\\testdemo\\myconvertstream\\utf-8file.txt", StandardCharsets.UTF_8);int ch;while ((ch = fr.read()) != -1) {fw.write(ch);}fw.close();fr.close();}
}

运行结果：

 

4.利用字节流读取文件中的数据，每次读一整行，而且不能出现乱码

public class ConvertStreamDemo4 {public static void main(String[] args) throws IOException {FileInputStream fis = new FileInputStream("chapter18\\src\\com\\testdemo\\myconvertstream\\gbkfile.txt");InputStreamReader isr = new InputStreamReader(fis, "GBK");BufferedReader br = new BufferedReader(isr);String ch;while ((ch = br.readLine()) != null) {System.out.println(ch);}br.close();}
}

运行结果：