实验01 掌握Servlet的生命周期.doc

Lecture01_Servlet目的：掌握Servlet的生命周期1创建一个基本的Servlet12，编写与HTML表单交互的Servlet23.Servlet中常用的操作44 测试应用ServletContext实现两个Servlet之间的通信55 Session和Cookie对象76用Servlet实现上课签到应用81创建一个基本的Servlet1.创建WEB项目，名为Lecture01_Servlet，使用默认的服务器Glassfish v2,不选择框架。2.新建一个Servleta指定类名为ServletBasicb按如下图指定Servlet的内部对象名称和外部访问URL模式c完成3.打开项目中WEB-INF文件夹下的web.xml，可以看到以下内容： myFirstServlet ServletBasic myFirstServlet /myServlet 注意它与以上向导操作的对应关系。取消ServletBasic类中的注解，运行项目。默认浏览器将被启动，服务器中的index.jsp页面将被运行在浏览器中输入：http:/localhost:8080/lecture01_Servlet/myServlet在页面中将看到输出内容：Servlet ServletBasic at /lecture01_Servlet注意：所输入的http:/localhost:8080/lecture01_Servlet/myServlet中myServlet是执行ServletBasic的URL用名称，lecture01_Servlet是站点路径名，前面部分http是协议名、localhost是主机名，8080是端口号。2，编写与HTML表单交互的Servlet右选项目名：新建HTML文件,输入HTML文件名login编辑login.html,将其中的body区替换为： 用户名： 口 令： 建立一个新的Servlet类名为ServletLogin，用于接收和处理该表单中输入的用户名和口令值。设置相应的URL为loginservlet。相应的processRequest方法代码为： protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException response.setContentType(text/html;charset=UTF-8); PrintWriter out = response.getWriter(); String name = request.getParameter(name); String password = request.getParameter(password); try out.println(); out.println(); out.println(Servlet ServletLogin); out.println(); out.println(); out.println(Hello + name + ,welcome !); out.println(I know your passowrd is + password + ); out.println(); out.println(); finally out.close(); 3.Servlet中常用的操作获得HTTP请求信息创建第三个Servlet，类名为ServletHttpRequest，URL访问名为myHttpRequestServlet将processRequest方法内容修改为： protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException response.setContentType(text/html;charset=UTF-8); PrintWriter out = response.getWriter(); try Enumeration e = request.getHeaderNames(); /请求头名枚举 while(e.hasMoreElements() /列出所有请求头属性值 String name = (String) e.nextElement(); String value = request.getHeader(name); out.println(name+ = +value+ ); finally out.close(); accept = */* accept-language = zh-cn accept-encoding = gzip, deflate user-agent = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; (R1 1.6); .NET CLR 2.0.50727; 360SE) host = localhost:8080 connection = Keep-Alive cookie = JSESSIONID=74a165c8774090fdba94a8534575运行：http:/localhost:8080/lecture01_Servlet/myHttpRequestServlet输出结果为：通过request对象获得其它请求信息：Method,RequestURI,Protocol,PathInfo,RemoteAddr向ServletHttpRequest类的processRequest方法中加入以下代码： out.println(请求方法Method: +request.getMethod() +); out.println(授权类型AuthType: +request.getAuthType() +); out.println(请求URI,RequestURI: +request.getRequestURI() +); out.println(请求协议Protocol: +request.getProtocol() +); out.println(远程用户RemoteUser: +request.getRemoteUser() +); out.println(访问源地址，RemoteAddr: +request.getRemoteAddr() +); out.println(会话ID，RequestedSessionId: +request.getRequestedSessionId() +);运行，将得到以下输出结果：请求方法Method: GET 授权类型AuthType: null 请求URI,RequestURI: /lecture01_Servlet/myHttpRequestServlet 请求协议Protocol: HTTP/1.1 远程用户RemoteUser: null 访问源地址，RemoteAddr: 会话ID，RequestedSessionId: 753fbed2de0300cfece11b32525e4 测试应用ServletContext实现两个Servlet之间的通信利用一个项目中唯一的共享上下文ServletContext对象实现两个或多个Servlet之间的通信。1 覆盖ServletBasic父类中的init方法，在该方法中向ServletContext中写入两个 属性值 对。 /覆盖init方法 public void init( ) throws ServletException ServletContext ctx = this.getServletContext(); /取得Servlet运行环境的上下文对象 ctx.setAttribute(ServletBasic_name, ServletBasic); /向运行环境写入一个属性和相关的值 ctx.setAttribute(ServletBasic_description, my first Servlet); 2 创建另一个Servlet，类名为：ServletSecond，URL访问名为mySecondServlet3 对ServletSecond的processRequest方法中加入代码： /测试Servlet之间的通信 ServletContext ctx = this.getServletContext(); /取得Servlet运行环境的上下文对象 String name = (String) ctx.getAttribute(ServletBasic_name); String desc = (String) ctx.getAttribute(ServletBasic_description); 去除原有的注释，加入以下两行：out.println(自SevletBasic读取的属性:ServletBasic_name= +name + );out.println(自SevletBasic读取的属性:ServletBasic_description= +desc + );4 运行项目自SevletBasic读取的属性:ServletBasic_name=Null自SevletBasic读取的属性:ServletBasic_description=Null先运行http:/localhost:8080/lecture01_Servlet/mySecondServlet，输出结果为：说明此时并没有两个属性的值。运行：http:/localhost:8080/lecture01_Servlet/myServlet再次运行：http:/localhost:8080/lecture01_Servlet/mySecondServlet，输出结果为：自SevletBasic读取的属性:ServletBasic_name=ServletBasic自SevletBasic读取的属性:ServletBasic_description=my first Servlet说明运行myServlet后，所设置的属性信息被mySeondServlet所取得。讨论与思考：1. 这种基于共享上下文的信息交换功能有什么用？可以用它解决哪些问题？2. 聊天程序？5 Session和Cookie对象创建一个Servelt，类名为ServletSession，访问URL为mySessionServletprocessRequest代码为： protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException response.setContentType(text/html;charset=UTF-8); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(); /取得 Session对象 try Date dateCreate = new Date(session.getCreationTime(); Date dateAccess = new Date(session.getLastAccessedTime(); out.println(Session ID =+session.getId()+); out.println(Create Date Time =+dateCreate+); out.println(Last Accessed Date Time =+dateAccess+); session.setAttribute(userName, lxy); /向Session中设置属性 session.setAttribute(passWord, 1234); / /输出所有的Session值和名 Enumeration attriNames = session.getAttributeNames(); /取得Session中的全部属性 while(attriNames.hasMoreElements() /输出属性和值 String atName = (String) attriNames.nextElement(); String atValue = (String) session.getAttribute(atName); out.println(Session 属性名：+atName+，值=+atValue+); finally out.close(); 创建一个Servelt，类名为ServletCookies，访问URL为myCookiesServletprocessRequest代码为： protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException response.setContentType(text/html;charset=UTF-8); PrintWriter out = response.getWriter(); Cookie cookies = request.getCookies(); for(Cookie c : cookies) String cname = c.getName(); String cvalue = c.getValue(); out.println(cname + = +cvalue+); /向cookies中添加属性 Cookie c1 = new Cookie(cookieAtt1,value1); Cookie c2 = new Cookie(cookieAtt2,value2); response.addCookie(c1); response.addCookie(c2); out.close(); 运行 http:/localhost:8080/lecture01_Servlet/myCookiesServlet注意：第一次运行，与第二次运行的区别思考与讨论：对上述Servlet可以作什么样的修改，得到一些有趣、有用的功能？6用Servlet实现上课签到应用实验内容：1. 在数据库中创建签到表2. 根据数据库创建实体类3. 根据实体类创建会话Bean4. 创建html页面，在表单中接收用户输入，提交到签到Servlet5. 创建签到Servlet，获取表单输入数据，应用会话Bean插入到数据库中。实验步骤：6.1. 在数据库中创建签到表在MySQL的test数据库中创建表signInCREATE TABLE signin ( stuNo CHAR(10) NOT NULL DEFAULT 0, signDate DATE NOT NULL DEFAULT 0000-00-00, name CHAR(20) NULL DEFAULT NULL, signTime DATETIME NULL, signIP CHAR(20) NULL,PRIMARY KEY (stuNo, signDate) ) 6.2 在WEB应用项目中基于数据库表创建实体类得到如下所示的实体类SignIn.javaEntityTable(name = signin)XmlRootElementNamedQueries( NamedQuery(name = Signin.findAll, query = SELECT s FROM Signin s), NamedQuery(name = Signin.findByStuNo, query = SELECT s FROM Signin s WHERE s.signinPK.stuNo = :stuNo), NamedQuery(name = Signin.findBySignDate, query = SELECT s FROM Signin s WHERE s.signinPK.signDate = :signDate), NamedQuery(name = Signin.findByName, query = SELECT s FROM Signin s WHERE = :name), NamedQuery(name = Signin.findBySignTime, query = SELECT s FROM Signin s WHERE s.signTime = :signTime), NamedQuery(name = Signin.findBySignIP, query = SELECT s FROM Signin s WHERE s.signIP = :signIP)public class Signin implements Serializable private static final long serialVersionUID = 1L; EmbeddedId protected SigninPK signinPK; Size(max = 20) Column(name = name) private String name; Column(name = signTime) Temporal(TemporalType.TIMESTAMP) private Date signTime; Size(max = 20) Column(name = signIP) private String signIP; public Signin() public Signin(SigninPK signinPK) this.signinPK = signinPK; public Signin(String stuNo, Date signDate) this.signinPK = new SigninPK(stuNo, signDate); public SigninPK getSigninPK() return signinPK; public void setSigninPK(SigninPK signinPK) this.signinPK = signinPK; public String getName() return name; public void setName(String name) = name; public Date getSignTime() return signTime; public void setSignTime(Date signTime) this.signTime = signTime; public String getSignIP() return signIP; public void setSignIP(String signIP) this.signIP = signIP; Override public int hashCode() int hash = 0; hash += (signinPK != null ? signinPK.hashCode() : 0); return hash; Override public boolean equals(Object object) / TODO: Warning - this method wont work in the case the id fields are not set if (!(object instanceof Signin) return false; Signin other = (Signin) object; if (this.signinPK = null & other.signinPK != null) | (this.signinPK != null & !this.signinPK.equals(other.signinPK) return false; return true; Override public String toString() return entities.Signin signinPK= + signinPK + ; 6.3 在WEB应用项目中基于实体类创建会话Bean得到如下所示的会话Bean:Statelesspublic class SigninFacade extends AbstractFacade PersistenceContext(unitName = lecture02PU) private EntityManager em; protected EntityManager getEntityManager() return em; public SigninFacade() super(Signin.class); 其中AbstractFacade为：public abstract class AbstractFacade private Class entityClass; public AbstractFacade(Class entityClass) this.entityClass = entityClass; protected abstract EntityManager getEntityManager(); public void create(T entity) getEntityManager().persist(entity); public void edit(T entity) getEntityManager().merge(entity); public void remove(T entity) getEntityManager().remove(getEntityManager().merge(entity); public T find(Object id) return getEntityManager().find(entityClass, id); public List findAll() javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery(); cq.select(cq.from(entityClass); return getEntityManager().createQuery(cq).getResultList(); public List findRange(int range) javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery(); cq.select(cq.from(entityClass); javax.persistence.Query q = getEntityManager().createQuery(cq); q.setMaxResults(range1 - range0); q.setFirstResult(range0); return q.getResultList(); public int count() javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery(); javax.persistence.criteria.Root rt = cq.from(entityClass); cq.select(getEntityManager().getCriteriaBuilder().count(rt); javax.persistence.Query q = getEntityManager().createQuery(cq); return (Long) q.getSingleResult().intValue(); 6.4 创建html页面 请签到 学号: 姓名： 6.4 创建响应页面请求的SignInServlet实现的代码如下：WebServlet(name = SignInServlet, urlPatterns = /si)public class SignInServlet extends HttpServlet EJB SigninFacade sf; /* * Processes requests for both HTTP GET and POST methods. * param request servlet request * param response servlet response * throws ServletException if a servlet-specific error occurs * throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException response.setContentType(text/html;charset=UTF-8); PrintWriter out = response.getWriter(); String stuNo =request.getParameter(stuNo).trim(); String name = request.getParameter(name);/ Signin