java中讲讲FileReader的用法，举例？

2.2 FileReader的用法

FileReader是Reader的继承类，从字面上就可看出，它的主要功能就是能从磁盘上读入文件。read方法会一个一个字符的从磁盘往回读数据。

例：2.2.1

import java.io.*;

public class TestMark_to_win {

public static void main(String args[]) throws Exception {

/*public int read()

throws IOException

Reads a single character.

Overrides:

read in class Reade

Returns:

The character read, or -1 if the end of the stream has been reached

Throws:

IOException - If an I/O error occurs */

int ii;

FileReader in = new FileReader("c:/1.txt");

while ((ii = in.read()) != -1) {

System.out.println(ii);

}

in.close();

FileReader in1 = new FileReader("c:/1.txt");

while ((ii = in1.read()) != -1) {

System.out.println((char)ii);

}

in1.close();

}

}

例：2.2.2（一个简单的拷贝方法，初学者方便理解）

import java.io.*;

public class TestMark_to_win {

public static void main(String[] args) throws IOException {

File inputFile = new File("c:/1.txt");

File outputFile = new File("c:/1_c.txt");

FileReader in = new FileReader(inputFile);

FileWriter out = new FileWriter(outputFile);

int c;

while ((c = in.read()) != -1)

out.write(c);

in.close();

out.close();

}

}

更多请见：https://blog.csdn.net/qq_44639795/article/details/102608738