JavaWeb Servlet技术及其应用实践

  <servlet>
    <servlet-name>TestServlet</servlet-name>
    <servlet-class>com.yuan.servlet.TestServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>TestServlet</servlet-name>
    <url-pattern>/testServlet</url-pattern>
  </servlet-mapping>

package com.yuan.servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/testServlet")
public class TestServlet extends HttpServlet {
    @Override
    public void init(ServletConfig config) throws ServletException {
        // 初始化方法
    }
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 服务方法
    }
    @Override
    public void destroy() {
        //销毁方法
    }
}

request.getRequestDispatcher( "目标页面" ) .forward( request, response );

response.sendRedirect( request.getContextPath() + "目标页面" ); 

// 添加属性
.setAttribute(key, value)
// 取属性值
.getAttribute(key)
// 移除属性
.removeAttribute(key)

// 接页面传来的值
String value = request.getParameter(key);   //接一个值
String[] vals = request.getParameterValues(key);  //接一组值
// 得到其它容器
HttpSession session = request.getSession();
ServletContext app = request.getServletContext();
// 得到URL 信息
StringBuffer url = request.getRequestURL();
String scheme = request.getScheme();
String serverName = request.getServerName();
int serverPort = request.getServerPort();
String uri = request.getRequestURI();
String cpath = request.getContextPath();       // 得到绝对路径
String servletUrl = request.getServletPath();  // 被请求servlet
String remoteAddr = request.getRemoteAddr();  // 得到客户端IP

// 取session 的 标识 id
String sid = session.getId();
// 获取最长等待时间
int max = session.getMaxInactiveInterval();
// 设置最长等待时间, 以秒为单位
session.setMaxInactiveInterval(len);
// 取所属的上下文
ServletContext app = session.getServletContext();

  <session-config>
    <session-timeout>30</session-timeout>
  </session-config>

// 取项目的真实路径(发布路径)
String path = app.getRealPath(path);
// 取 web.xml 中设置的参数
String pv = app.getInitParameter(paramName);

  <context-param>
    <param-name>paramName</param-name>
    <param-value>paramValue</param-value>
  </context-param>

public void init(ServletConfig config) throws ServletException {
    // 取web.xml 文件中在<servlet></servlet>下的信息
	String icon = config.getInitParameter(configName);
	// 取所属的上下文
	ServletContext app = config.getServletContext();
}

  <servlet>
    <init-param>
      <param-name>configName</param-name>
      <param-value>configValue</param-value>
    </init-param>
    <servlet-name>TestServlet</servlet-name>
    <servlet-class>com.yuan.servlet.TestServlet</servlet-class>
  </servlet>