java读取文件

package com.yang;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class FileDemo1 {
public static void main(String[] args) throws IOException {
1.读取文件内容的第一种方法 单个字节进行读取
String filePath = “D:\yangshen\h1.txt”;
File file = new File(filePath);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}

    FileInputStream fileInputStream = null;
    try {
        fileInputStream = new FileInputStream(filePath);
        while ((readData = fileInputStream.read())!= -1) {
            System.out.print((char)readData);
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        fileInputStream.close();
    }


    2.读取文件内容的第一种方法 多个字节进行读取


    byte[] bytes = new byte[6];//一次读取四个字节
    FileInputStream fileInputStream = null;
    fileInputStream = new FileInputStream(filePath);
    int readLen = fileInputStream.read(bytes);
    System.out.println(readLen);//第一次读取到了6个字节
    readLen = fileInputStream.read(bytes);
    System.out.println(readLen);//第二次读取到了2个字节



    3.读取文件内容的最终版
    String filePath = "D:\\yangshen\\h1.txt";
    FileInputStream fileInputStream = null;
    try {
        fileInputStream = new FileInputStream(filePath);
        byte[] bytes = new byte[4];//每一次读取四个字节
        int readCount = 0;
        while ((readCount = fileInputStream.read(bytes)) != -1) {
            System.out.print(new String(bytes,0,readCount));//将字节数组转换为字符串
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } finally {
        fileInputStream.close();
    }

}

}