基于JDK6/JAVAEE6
Web容器：Tomcat7以上
Myeclipse 9.0（或者在8基础上自己扩展）
Servlet2.5的配置
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
?????????????????? xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
?????????????????? xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
?????????????????? http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
?
Servlet3.0的配置
<web-app version="3.0"
?????? xmlns="http://java.sun.com/xml/ns/javaee"
?????? xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
?????? xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
?????? http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
?
通过在java类里面使用Annotation注解的方式来配置servlet的名称和urlPattern
这样就不需要再在web.xml里配置了
@WebServlet(name = "firstServlet", urlPatterns = { "/firstServlet",
????????????? "/myDefaultServlet" })
// 可以指定多个映射
public class FirstServlet extends HttpServlet {
?
?????? private static final long serialVersionUID = 6531730293401271095L;
?
?????? @Override
?????? protected void doGet(HttpServletRequest req, HttpServletResponse resp)
???????????????????? throws ServletException, IOException {
????????????? resp.getWriter().write("this is my first Servlet");
?????? }
}
位于javax.servlet.annotation包下
Name：配置servlet的名称
Value/urlPatterns：2个都可以指定serlvet-urlPattern，多个使用{}
loadOnStartup：servlet的load-on-startup顺序
initParams：初始化参数
注意，必须使用@WebInitParam(name=”xxx”,value=”xxx”)
如initParams = {@WebInitParam(name=”xxx”,value=”xxx”), @WebInitParam(name=”xxx”,value=”xxx”)}
asyncSupported：是否支持异步，默认为false
?
上面也用到了，只有2个属性name和value
2种用法：
A、 嵌入到@WebServlet的initParams参数里
B、 直接定义（可重复使用）
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AsyncContext sc = request.startAsync(request, response);
????????????? sc.addListener(new MySyncListener());
?
class MySyncListener implements AsyncListener {
?
?????? @Override
?????? public void onComplete(AsyncEvent arg0) throws IOException {
????????????? System.out.println("syncContext is complete");
?
?????? }
?
?????? @Override
?????? public void onError(AsyncEvent arg0) throws IOException {
????????????? // TODO Auto-generated method stub
?
?????? }
?
?????? @Override
?????? public void onStartAsync(AsyncEvent arg0) throws IOException {
????????????? // TODO Auto-generated method stub
?
?????? }
?
?????? @Override
?????? public void onTimeout(AsyncEvent arg0) throws IOException {
????????????? // TODO Auto-generated method stub
?
?????? }
?
}
在代码里实现注册，目前只支持ServletContext容器启动的时候注册，不支持运行中注册
?
如下例子
//不注解，也不在web.xml中配置，而是通过动态注册的方式
public class DynamicServlet extends HttpServlet {
?????? public void doGet(HttpServletRequest request, HttpServletResponse response)
???????????????????? throws ServletException, IOException {
?
????????????? response.setContentType("text/html");
????????????? PrintWriter out = response.getWriter();
????????????? out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
????????????? out.println("<HTML>");
????????????? out.println("? <HEAD><TITLE>A Servlet</TITLE></HEAD>");
????????????? out.println("? <BODY>");
????????????? out.print("??? This is ");
????????????? out.print(this.getClass());
????????????? out.println(", using the GET method");
????????????? out.println("? </BODY>");
????????????? out.println("</HTML>");
????????????? out.flush();
????????????? out.close();
?????? }
?
}
?
在有ServletContext的地方就可以注册该Serlvet，如下
@WebListener
public class MyListener2 implements ServletContextListener {
?????? @Override
?????? public void contextDestroyed(ServletContextEvent arg0) {
?????????????
?????? }
?
?????? @Override
?????? public void contextInitialized(ServletContextEvent se) {
????????????? System.out.println("servletContext init");
?????????????
????????????? //动态注册Servlet
????????????? ServletRegistration sr = se.getServletContext().addServlet("DynamicServlet", "com.lxh.servlet.DynamicServlet");
????????????? sr.addMapping("/DynamicServlet");
????????????? sr.addMapping("/DynamicServlet2");//可增加多个mapping
?????????????
?????? }
}
?
这样的好处是，假设给现有系统增加一个servlet，我们只需要自己编写完后打成jar包放在现有系统下即可。对原有代码不需要做任何改动。
上面在Servlet就已经使用到了
Optional Element Summary
?java.lang.String
value
??????????Description of the listener
?
不需要参数，不需要在web.xml中配置了，如下代码，tomcat启动的时候将会捕捉到
@WebListener
public class MyListener2 implements ServletContextListener {
?
?????? @Override
?????? public void contextDestroyed(ServletContextEvent arg0) {
????????????? // TODO Auto-generated method stub
?????????????
?????? }
?
?????? @Override
?????? public void contextInitialized(ServletContextEvent arg0) {
????????????? System.out.println("servletContext init");
?????????????
?????? }
?
}
?
Optional Element Summary
?boolean
asyncSupported
??????????Declares whether the filter supports asynchronous operation mode.
?java.lang.String
description
??????????The description of the filter
?DispatcherType[]
dispatcherTypes
??????????The dispatcher types to which the filter applies
?java.lang.String
displayName
??????????The display name of the filter
?java.lang.String
filterName
??????????The name of the filter
?WebInitParam[]
initParams
??????????The init parameters of the filter
?java.lang.String
largeIcon
??????????The large-icon of the filter
?java.lang.String[]
servletNames
??????????The names of the servlets to which the filter applies.
?java.lang.String
smallIcon
??????????The small-icon of the filter
?java.lang.String[]
urlPatterns
??????????The URL patterns to which the filter applies
?java.lang.String[]
value
??????????The URL patterns to which the filter applies
?
@WebFilter(filterName="myFilter",urlPatterns="/*")
public class MyFilter implements Filter {
?
?????? @Override
?????? public void destroy() {
????????????? // TODO Auto-generated method stub
?????????????
?????? }
?
?????? @Override
?????? public void doFilter(ServletRequest arg0, ServletResponse arg1,
???????????????????? FilterChain arg2) throws IOException, ServletException {
????????????? // TODO Auto-generated method stub
?????????????
?????? }
?
?????? @Override
?????? public void init(FilterConfig arg0) throws ServletException {
????????????? // TODO Auto-generated method stub
?????????????
?????? }
?
}
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