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();
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
