import javax.servlet.http.WebConnection; //导入依赖的package包/类
@Override
public void init(final WebConnection wc) {
    Listener listener = null;
    try {
        listener = new Listener(wc);
      
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
      
    try {
        
        if (Log.doTrace()) {
            Log.trace("PingUpgradeServlet$Handler.init() -- Initializing Handler");
        }
  
        // flush headers if any
        wc.getOutputStream().flush();
        wc.getInputStream().setReadListener(listener);

    } catch (IOException e) {
        throw new IllegalArgumentException(e);
    }
}
 

import javax.servlet.http.WebConnection; //导入依赖的package包/类
@Override
public void init(WebConnection wc) {
	try (ServletInputStream input = wc.getInputStream(); ServletOutputStream output = wc.getOutputStream();) {
		output.write(("upgrade" + CRLF).getBytes());
		output.write(("received" + CRLF).getBytes());
		output.write("END".getBytes());
	} catch (IOException ex) {
	}
}
 

import javax.servlet.http.WebConnection; //导入依赖的package包/类
@Override
public void init(WebConnection wc) {
    try (ServletInputStream input = wc.getInputStream();
        ServletOutputStream output = wc.getOutputStream();) {
    } catch (IOException ex) {
    }
}
 

import javax.servlet.http.WebConnection; //导入依赖的package包/类
@Override
public void init(WebConnection wc) {
    close(wc::getInputStream);
    close(wc::getOutputStream);
}
 

import javax.servlet.http.WebConnection; //导入依赖的package包/类
private Listener(final WebConnection connection) throws IOException  {
    this.connection = connection;
    this.input = connection.getInputStream();
    this.output = connection.getOutputStream();
}