IO流（4）FileReader和FileWriter

FileReader和FileWriter是字符流，即按照字符来操作io

Reader

@Test
    public void fileReader02(){
        //字符数组字符读取文件
        String filePath = "e:\\hello.txt";

        java.io.FileReader fileReader = null;
        char[] buf = new char[10];
        int readlen = 0;
        try {
            fileReader = new java.io.FileReader(filePath);
            //循环读取，使用read(buf),返回的是实际读取到的字符数

            while((readlen = fileReader.read(buf))!=-1){
                System.out.print(new String(buf,0,readlen));
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                fileReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

Writer

package IO.writer;

import java.io.IOException;

public class FileWriter {
    public static void main(String[] args) {
        String filePath = "e:\\news1.txt";
        char[] chars = {'a','b','c'};
        java.io.FileWriter fileWriter = null;

        try {

            fileWriter = new java.io.FileWriter(filePath);
            //1.write(int):写入单个字符
            fileWriter.write('H');
            //2.write(char[]):写入指定数组
            fileWriter.write(chars);
            //3.write(char[],off,len):写入指定数组的制定部分
            fileWriter.write("长空扯淡".toCharArray(),0,3);
            //4.write(string):写入整个字符串
            fileWriter.write(" 天天下雪");
            //5.write(string,off,len):写入字符串的指定部分
            fileWriter.write("长空扯淡",0,2);

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                //fileWriter.flush();
                //关闭文件流等价用户  刷新加关闭
                fileWriter.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        System.out.println("结束");
    }
}