Java使用FileInputStream / FileOutputStream读/写文件
示例
写入文件test.txt：
String filepath ="C:\\test.txt";
FileOutputStream fos = null;
try {
fos = new FileOutputStream(filepath);
byte[] buffer = "This will be written in test.txt".getBytes();
fos.write(buffer, 0, buffer.length);
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally{
if(fos != null)
fos.close();
}从文件test.txt中读取：
String filepath ="C:\\test.txt";
FileInputStream fis = null;
try {
fis = new FileInputStream(filepath);
int length = (int) new File(filepath).length();
byte[] buffer = new byte[length];
fis.read(buffer, 0, length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally{
if(fis != null)
fis.close();
}请注意，自Java1.7起引入了try-with-resources语句，这使得读/写操作的实现更加简单：
写入文件test.txt：
String filepath ="C:\\test.txt";
try (FileOutputStream fos = new FileOutputStream(filepath)){
byte[] buffer = "This will be written in test.txt".getBytes();
fos.write(buffer, 0, buffer.length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}从文件test.txt中读取：
String filepath ="C:\\test.txt";
try (FileInputStream fis = new FileInputStream(filepath)){
int length = (int) new File(filepath).length();
byte[] buffer = new byte[length];
fis.read(buffer, 0, length);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}