这篇文章主要介绍了java io读取文件操作代码实例,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

主要分为字节读取和字符读取，字节读取可以一个一个读取和字节数组读取，字符读取同样之，字符读取适合文本读取，字节读取皆可以

这里直接上代码，读取文件的9个小demo

package com.io;

import org.junit.Test;

import java.io.*;

public class FileTest {

//1、字节流字节一个一个读取

@Test

public void test() throws IOException{

InputStream fis = new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"));

int len;

//按字节一个一个读取

while ((len = fis.read())!=-1){

System.out.print((char)len+"t");

};

fis.close();

}

//输出结果h e l l o w o r l d

//2、字节流字节数组读取

@Test

public void test1() throws IOException{

InputStream fis = new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"));

byte[] bytes = new byte[2];

int len ;

//按字节数组读取 bytes存储的是读取的数据

while ((len = fis.read(bytes))!=-1){

System.out.print((new String(bytes))+"t");

};

fis.close();

}

//输出结果 he ll ow or ld

//3、缓冲字节流字节一个一个读取

@Test

public void test2() throws IOException{

BufferedInputStream bis = new BufferedInputStream(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));

int len ;

while ((len = bis.read())!=-1){

System.out.print((char)len+"t");

};

bis.close();

}

//输出结果h e l l o w o r l d

//4、缓冲字节流字节数组读取

@Test

public void test3() throws IOException{

BufferedInputStream bis = new BufferedInputStream(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));

byte[] bytes = new byte[3];

int len ;

//按字节数组读取 bytes存储的是读取的数据

while ((len = bis.read(bytes))!=-1){

System.out.print(new String(bytes)+"t");

};

bis.close();

}

//输出结果hel low orl drl

//5、字符流一个一个读取

@Test

public void test4() throws IOException{

InputStreamReader isr = new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));

int len ;

//按字节数组读取 bytes存储的是读取的数据

while ((len = isr.read())!=-1){

System.out.print((char)len+"t");

};

isr.close();

}

//6、字符流字符数组读取

@Test

public void test5() throws IOException{

InputStreamReader isr = new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));

char[] chars = new char[3];

int len ;

//按字节数组读取 bytes存储的是读取的数据

while ((len = isr.read(chars))!=-1){

System.out.print(new String(chars)+"t");

};

isr.close();

}

//7、缓冲字符流字符一个一个读取

@Test

public void test6() throws IOException{

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"))));

int len ;

//按字节数组读取 bytes存储的是读取的数据

while ((len = br.read())!=-1){

System.out.print((char)len+"t");

};

br.close();

}

//8、缓冲字符流字符数组读取

@Test

public void test7() throws IOException{

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"))));

char[] chars = new char[3];

int len ;

//按字节数组读取 bytes存储的是读取的数据

while ((len = br.read(chars))!=-1){

System.out.print(new String(chars)+"t");

};

br.close();

}

//9、缓冲字符流按行读取

@Test

public void test8() throws IOException{

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"))));

//按字节数组读取 bytes存储的是读取的数据

String str;

while ( (str = br.readLine())!=null){

System.out.print(str+"t");

};

br.close();

}

}

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