2.字符IO流

@SuppressWarnings("all")
public class CharStreamMax {
    FileReader fileReader = null;
    FileWriter fileWriter = null;
    //打印文件内容
    public void inPut() throws IOException {
        File file = new File("D:\\IdeaProjects\\javase\\src\\test.txt");
        fileReader = new FileReader(file);
        char[] chars = new char[1024];
        while (fileReader.read(chars) != -1) {
            System.out.print(String.valueOf(chars));
        }
        System.out.println("\n");
        fileReader.close();
    }
    //修改文件内容
    public void outPut() throws IOException {
        File file1 = new File("D:\\IdeaProjects\\javase\\src\\test.txt");
        File file2 = new File("D:\\IdeaProjects\\javase\\src\\IOStream2");
        //读取file2的内容
        fileReader = new FileReader(file2);
        //将file2的内容写入到file1中
        fileWriter = new FileWriter(file1);
        char[] chars = new char[1024];
        int len = 0;
        while ((len = fileReader.read(chars)) != -1) {
            fileWriter.write(chars,0,len);
        }
        fileReader.close();
        fileWriter.flush();
        fileWriter.close();
    }
    public static void main(String[] args) throws IOException {
        CharStreamMax charStreamMax = new CharStreamMax();
        //打印文件内容
        charStreamMax.inPut();
        //修改文件内容
        charStreamMax.outPut();
        //再次打印文件内容，检测是否已修改
        charStreamMax.inPut();
    }
}