inputstream.read()
时间: 2023-04-24 07:04:58 浏览: 71
inputstream.read()是Java中InputStream类的一个方法,用于从输入流中读取下一个字节的数据。该方法返回一个整数值,表示读取的字节数据,如果已经到达输入流的末尾,则返回-1。
相关问题
InputStream.read
(InputStream.java)
The read() method of the InputStream class reads a single byte of data from the input stream and returns it as an integer value. If the end of the stream is reached, the method returns -1.
Syntax:
public abstract int read() throws IOException
Parameters:
This method does not take any parameters.
Return Value:
Returns an integer value that represents the byte read from the input stream. If the end of the stream is reached, the method returns -1.
Exceptions:
This method throws an IOException if an I/O error occurs while reading from the input stream.
Example:
The following example reads a file using a FileInputStream object and prints the contents of the file to the console.
import java.io.*;
public class ReadFileExample {
public static void main(String[] args) {
try {
FileInputStream inputStream = new FileInputStream("file.txt");
int data;
while ((data = inputStream.read()) != -1) {
System.out.print((char) data);
}
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
InputStream.read具体用法
InputStream.read() 方法是用来读取输入流中的字节数据的。它的具体用法如下:
1. 读取单个字节:
```
int b = inputStream.read();
```
该方法会从输入流中读取一个字节,如果已经到了流的末尾,它会返回-1。
2. 读取字节数组:
```
byte[] buffer = new byte[1024];
int length = inputStream.read(buffer);
```
该方法会从输入流中读取最多 buffer.length 个字节,并将其存储在 buffer 数组中。它返回实际读取的字节数。如果已经到了流的末尾,它会返回-1。
3. 读取部分字节数组:
```
byte[] buffer = new byte[1024];
int offset = 0;
int length = 1024;
while (length > 0) {
int bytesRead = inputStream.read(buffer, offset, length);
if (bytesRead == -1) {
break;
}
offset += bytesRead;
length -= bytesRead;
}
```
该方法会从输入流中读取最多 length 个字节,并将其存储在 buffer 数组中,从偏移量 offset 开始存储。它返回实际读取的字节数。如果已经到了流的末尾,它会返回-1。
4. 关闭输入流:
```
inputStream.close();
```
该方法会关闭输入流并释放与之相关的资源。如果输入流已经关闭,它会抛出一个 IOException 异常。因此,在使用完输入流后,应该及时关闭它。