java 文件操作

java读文件

 1 import java.io.BufferedReader;
 2 import java.io.BufferedWriter;
 3 import java.io.FileInputStream;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.InputStreamReader;
 7 import java.io.OutputStreamWriter;
 8 
 9 public class ReaderTest1 {
10     public static void main(String[] args) throws IOException{
11         reader();
12     }
13     public static void reader() throws IOException {
14         //定义一个指向c:\\x.txt的字节流
15         FileInputStream fis = new FileInputStream("C:\\x.txt");
16         //字节流转换成InputStreamReader
17         InputStreamReader isr = new InputStreamReader(fis);
18         //InputStreamReader 转换成带缓存的bufferedReader
19         BufferedReader bufferedReader = new BufferedReader(isr);
20         //将读取出来的信息赋值给字符串s
21         String ss = new String();
22         String s;
23         while ((s = bufferedReader.readLine())!=null) {
24             ss += s;
25         }
26         //定义一个指向输出的字节流
27         FileOutputStream fos = new FileOutputStream("D:\\x.txt");
28         //字节流转换成outputStreamWriter
29         OutputStreamWriter osw = new OutputStreamWriter(fos);
30         //outputStreamWriter 转换成带缓存的bufferedReader
31         BufferedWriter bufferedWriter = new BufferedWriter(osw);
32         bufferedWriter.write(ss);
33         bufferedWriter.close();
34         osw.close();
35         fos.close();
36         
37     }
38 }

 追加内容

 1 import java.io.FileOutputStream;
 2 import java.io.IOException;
 3 
 4 public class FileOutputStreamtrueTest {
 5     public static void fileInputStreamTest() throws IOException {
 6         String filename;
 7         filename = "C:\\a.txt";
 8         String hello = "hello java";
 9         FileOutputStream fos = new FileOutputStream(filename,true);
10         byte b[] = hello.getBytes();
11         fos.write(b);
12         fos.close();
13     }
14     public static void main(String[] args) throws IOException {
15         fileInputStreamTest();
16     }
17 }

 

转载于:https://www.cnblogs.com/CheeseZH/archive/2013/03/25/2980999.html