在Java中，文件輸入流(FileInputStream)是一種用於讀取文件中的字節一個字節流類。下麵的例子將使用文件輸入流讀取一個名為 “c:/robots.txt” 文件並顯示其內容在控製台中。
//This is content of file : c:/robots.txt User-agent: * Disallow: /wp-admin/ Disallow: /wp-includes/ Disallow: /wp-includes-test/
請參閱下麵的完整的例子。
package com.yiibai.io;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
public class ReadFileExample {
public static void main(String[] args) {
File file = new File("C:/robots.txt");
FileInputStream fis = null;
try {
fis = new FileInputStream(file);
System.out.println("Total file size to read (in bytes) : "
+ fis.available());
int content;
while ((content = fis.read()) != -1) {
// convert to char and display it
System.out.print((char) content);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (fis != null)
fis.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
下麵的結果將顯示在控製台上。
Total file size to read (in bytes) : 90 User-agent: * Disallow: /wp-admin/ Disallow: /wp-includes/ Disallow: /wp-includes-test/
JDK 7 實例
更新 JDK7 實例，使用新的“嘗試資源接近”方法來輕鬆處理文件。
package com.yiibai.io;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
public class ReadFileExample {
public static void main(String[] args) {
File file = new File("C:/robots.txt");
try (FileInputStream fis = new FileInputStream(file)) {
System.out.println("Total file size to read (in bytes) : "+ fis.available());
int content;
while ((content = fis.read()) != -1) {
// convert to char and display it
System.out.print((char) content);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
