详解

/**
 * @classDesc: 功能描述:(线程不安全演示)
 */
@WebServlet("/ServletlDemo")
public class ServletlDemo extends HttpServlet {
	private int i = 1;
 
	@Override
	public void init() throws ServletException {
		System.out.println("ServletlDemo...init()");
	}
 
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		resp.setCharacterEncoding("utf-8");// 内容编码，防止出现中文乱码
		resp.setContentType("text/html;charset=utf-8");
			// 向浏览器输出内容
			resp.getWriter().write("这是第" + i + "次访问...");
			i++;
	}
 
	@Override
	public void destroy() {
		System.out.println("ServletlDemo...destroy()");
 
	}
}

@WebServlet("/ServletDemo")
public class ServletDemo extends HttpServlet {
	private int i = 1;
 
	@Override
	public void init() throws ServletException {
		System.out.println("ServletDemo...init()");
	}
 
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		resp.setCharacterEncoding("utf-8");// 内容编码，防止出现中文乱码
		resp.setContentType("text/html;charset=utf-8");
		synchronized (ServetlDemo.class) {
			// 向浏览器输出内容
			resp.getWriter().write("这是第" + i + "次访问...");
			try {
				Thread.sleep(5000);
			} catch (Exception e) {
			}
			i++;
		}
	}
 
	@Override
	public void destroy() {
		System.out.println("ServletDemo...destroy()");
	}
}