文件字符输入输出流

1、FileReader类

FileReader继承自InputStreamReader类，InputStreamReader类继承自Reader类。

import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;

public class FileReaderDemo {
    public static void main(String[] args) throws IOException {
        //读取文字
        FileReader fr = new FileReader("E:\\IO流\\java\\1.txt");
        int ch = 0;
        while ((ch = fr.read()) != -1) {
            // 输出的字符对应的编码值
            System.out.print(ch);
            System.out.print((char) ch);
            System.out.println();
        }
        //写入文字
        FileOutputStream fos = new FileOutputStream("E:\\IO流\\java\\8.txt");
        fos.write("读取文件".getBytes());//编码过程
        fos.close();

    }
}

2、使用FileWriter类向文件写入数据：

import java.io.FileWriter;
import java.io.IOException;
public class FileWriterDemo {
public static void main(String[] args) throws IOException {
    FileWriter fw = new FileWriter("E:\\IO流\\java\\1.txt");
    char []c={'n','i','h','a','o'};
    String str="我爱java";
    fw.write(c);
    fw.write("\t\n"+"你好java"+"\t\n");//先编码
    fw.write(str, 0, 2);
    fw.flush();
    fw.close();

}
}

3、应用（缓冲数组实现复制）

package pers.zzx.copy;

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class CopyDemo {
    public static void main(String[] args) throws IOException {
        FileWriter fw = new FileWriter("E:\\IO流\\java\\001.txt");
        FileReader fr = new FileReader("E:\\IO流\\java\\1.txt");
        char[] buf = new char[1024];
        int len = 0;
        while ((len = fr.read(buf)) != -1) {
            fw.write(buf, 0, len);
            System.out.println(len);
        }
        System.out.println(len);
        fw.close();
        fr.close();

    }
}

来源：https://www.cnblogs.com/zhai1997/p/11366598.html

标签

filereader