Java基础(3)：文件输入输出

最新推荐文章于 2024-03-05 13:47:59 发布

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本文详细介绍了Java中文件的输入输出方式，包括字节流和字符流的使用方法及示例。

Java文件的输入输出方式包括按字节流输入输出和按字符字符输入输出。

字节流

字节流的输入包括：Inputstream,FileInputStream,BufferedInputStream,DataInputStream;输出包括：Outputstream,FileOutputStream,BufferedOutputStream,DataOutputStream。

示例1：

public class FileIOTest {

@Test
public void test() throws IOException {

InputStream in = null;
OutputStream out= null;
try {
in=new FileInputStream("C:read.txt");
out=new FileOutputStream("C:write.txt");
byte []by=new byte[1024];
int ch;
while((ch=in.read(by))!=-1){
out.write(by);

out.flush();
}

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
in.close();
out.close();
}
}

}

示例2：

public class FileIOTest {

@Test
public void test() throws IOException {

BufferedInputStream in = null;
BufferedOutputStream out= null;
try {
in=new BufferedInputStream(new FileInputStream("C:read.txt"));
out=new BufferedOutputStream(new FileOutputStream("C:write.txt"));
byte []by=new byte[1024];
int ch;
while((ch=in.read(by))!=-1){
out.write(by);

out.flush();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
in.close();
out.close();
}
}

}

BufferedInputStream和BufferedOutputStream都是将内容先放在缓冲区，然后进行处理，效率更高。

字符

字符的输入包括：Reader，FileReader，BufferedReader；输出包括：Writer，FileWriter，BufferedWriter。

示例1：

public class FileIOTest {

@Test
public void test() throws IOException {

Reader in = null;
Writer out= null;
try {
in=new FileReader("C:read.txt");
out=new FileWriter("C:write.txt");
int line;
while((line=in.read())!=-1){
out.write((char)line);
System.out.println((char)line);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
in.close();
out.close();
}
}

}

示例2：

public class FileIOTest {

@Test
public void test() throws IOException {

BufferedReader in = null;
BufferedWriter out= null;
try {
in=new BufferedReader(new FileReader("C:read.txt"));
out=new BufferedWriter(new FileWriter("C:write.txt"));
String line;
while((line=in.readLine())!=null){
out.write(line);
System.out.println(line);
}
//out.flush();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
in.close();
out.close();
}
}

}