客户端Java服务器非阻塞查询
我使用以下代码从Android客户端读取一些数据。一切都很好。但现在我被要求让这个服务器代码不被阻塞。有什么建议吗?我试图使用线程,但不知道如何使用?我是Java初学者:)
谢谢
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Calendar;
import java.util.Date;
import javax.imageio.ImageIO;
public class Server {
//Server Constructor
public Server()
{}
//Variables Initialization
private static ServerSocket server;
byte[] imagetemp;
private static Socket socket1;
private static boolean newImage;
private static Sdfdata data;
private static boolean cond;
public static int port;
private static int number = 0;
//Image Availability return method
public boolean imageAvailable()
{
return newImage;
}
public boolean clientchk()
{
return socket1.isClosed();
}
//Image Flag set by Vis group when image read.
public void setImageFlag(boolean set)
{
newImage = set;
}
// Send the data to the Vis Group
public Sdfdata getData()
{
return data;
}
//Starts the Server
public static boolean start(int port1)
{
try {
port=port1;
server = new ServerSocket(port1);
System.out.println("Waiting for Client to Connect");
//New thread here
socket1=server.accept();
} catch (IOException e) {
System.out.println("Cannot Connect");
e.printStackTrace();
return false;
}
return true;
}
//Stops the Server
public boolean stop()
{
try {
socket1.close();
}
catch (IOException e)
{
e.printStackTrace();
return false;
}
return true;
}
/**
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
// Starts the server
start(4444);
// DataInput Stream for reading the data
DataInputStream in = null;
try {
in = new DataInputStream(socket1.getInputStream());
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
cond=true;
do {
try
{
//Read Image Data
int length = in.readInt();
//Create an ByteArray of length read from Client for Image transfer
Sdfdata data = new Sdfdata(length);
//for (int i=0; i<length; i++)
//{ data.image[i] = in.readbyte(); }
if (length > 0) {
in.readFully(data.image);
}
//Read Orientation
data.orientation[0] = in.readFloat(); //Orientation x
data.orientation[1] = in.readFloat(); //Orientation y
data.orientation[2] = in.readFloat(); //Orientation z
//Read GPS
data.longitude = in.readDouble();
data.latitude = in.readDouble();
data.altitude = in.readDouble();
//Display orientation and GPS data
System.out.println(data.orientation[0] + " " + data.orientation[1] + " " + data.orientation[2]);
System.out.println(data.longitude + " " + data.latitude + " " + data.altitude);
String fileName = "IMG_" + Integer.toString(++number) + ".JPG";
System.out.println("FileName: " + fileName);
FileOutputStream fos = new FileOutputStream(fileName);
fos.write(data.image);
fos.close();
/*InputStream ins = new ByteArrayInputStream(data.image);
BufferedImage image = ImageIO.read(ins);
ImageIO.write(image, "JPG", new File (fileName));
*/
//set image flag
newImage = true;
} catch (Exception e) {
//System.out.println("EOF Or ? " + e);
cond =false;
socket1.close();
server.close();
start(port);
}
}while (cond);
}
}
# 1 楼答案
代码启动服务器,等待连接,从第一个连接的客户端读取一些数据,然后将这些数据写入文件后退出
被要求使服务器“非阻塞”可能意味着你被要求将其更改为使用异步IO(可能不太可能),也可能意味着你被要求一次处理多个客户机——因为目前你只能为一个客户机服务,然后你的程序退出
这个问题很难回答,因为您当前的代码离您需要的地方很远,一般来说,阅读网络、套接字和Java编程似乎是一个很好的开始
我推荐Netty用Java做任何与网络相关的事情,它们的示例和文档都很好,而且易于理解。祝你好运