2月6日——培训第65天

春节前的最后一天课……班里面现在连一半人都不到了……

BBS逻辑层和数据层封装：

新建Web工程mybbs，加入Struts特性。

加入Hibernate特性：数据源名称：java:comp/env/jdbc/datadialect名称：MySQL

meta-inf里面建立一个context.xml:把数据源的东西拷贝进去<Context path="/mybbs" docBase="mybbs"> <Resource name="jdbc/data" auth="" type=""………………………… ……………………url="……………………………………"></Context>

加入Hibernate的特性的过程中可以选择生成Session和SessionFactory的类。添加show_sql和format_sql属性为true---------------------------------------system.properties:

characterEncoding=gbk---------------------------------------org.mybbs.util包里面新建SystemConfig：

public class SystemConfig(作用：去读取资源包){ public static ResourceBundle bundle = ResourceBundle          .getBundle("system"); public static final String CHARACTER_ENCODING = "characterEncoding"; //做成静态的，根据属性名得到属性值 public static String getProperty(String name) {  String s = null ;  try  {   s = bundle.getString(name);  }  catch(RuntimeException e)  {   e.printStackTrace() ;  }  return s ; }

 public static String getCharacterEncoding() {  return getProperty(SystemConfig.CHARACTER_ENCODING); }}

BBSActionServlet：package org.mybbs.action;public class BBSActionServlet extends ActionServlet{ protected void process(HttpServletRequest request,HttpServletResponse response) {  request.setCharacterEncoding(SystemConfig.getCharacterEncoding());  response.setCharacterEncoding(SystemConfig.getCharacterEncoding());  super.process(request,response);//这句话一定不能丢！！！ }

}

既然重写了ActionServlet，那么必须修改ActionServlet中的配置！

<servlet-class>org.mybbs.action.BBSActionServlet</servlet-class>

现在重新实现Action：package org.mybbs.action;public class GeneralAction extends Action{ //查询返回集合。这里面涉及分页的问题 protected List query(HttpServletRequest request,Class clazz,boolean needPagination) {  List list = null ;  if(needPagination)  {   Pagination pagination = new Pagination() ;   list = pagination.getNextPage(request,clazz) ;  }  else  {   Session session = null ;   try   {    session = HibernateSessionFactory.getSession() ;    session.beginTransaction() ;    list = session.createCriteria(clazz).list();                 session.getTransaction().commit();   }   catch(HibernateException e)   {    if(session!=null&&session.getTransaction()!=null)    {     session.getTransaction().rollback();    }    e.printStackTrace()；   }   finally   {    HibernateSessionFactory.closeSession() ;   }  }  return list ; }  //封装插入功能，将异常全部抛给客户端，让struts去处理 protected void save(Class clazz Map map) throws Exception {  Session session = null;

  Object obj = null ;  obj = clazz.newInstance() ;  BeanUtils.populate(obj,map) ;    if(obj!=null)  {   try   {    session = HibernateSessionFactory.getSession();    session.beginTransaction();    session.save(obj);    session.getTransaction().commit();   }   catch(HibernateException e)   {    if(session!=null && session.getTransaction()!=null)    {     session.getTransaction().rollback() ;    }    e.printStackTrace() ;   }   finally   {    HibernateSessionFactory.closeSession() ;   }  }   }

 protected void modify(Object obj) throws Exception {   }

 protected void delete(Object obj) throws Exception {  }

}

package org.mybbs.util;//解决分页问题：public class Pagination{ private int perPage = Pagination.defaultPerPage ;//每页显示条目 private int page = 1; //当前的页数  public static final String PER_PAGE = "org.mybbs.per_page" ; public static final String PAGE = "org.mybbs.page" ; public static final String TOTAL_PAGE = "org.mybbs.total_page";

 public static int defaultPerPage = 2 ; //生成getters和setters方法 public List getNextPage(HttpServletRequest request,Class clazz) {  List result = null ;

  Session session = null ;    String perPageStr = request.getParameter(Pagination.PER_PAGE);  String pageStr = request.getParameter(Pagination.PAGE) ;    try  {   page = Integer.parseInt(pageStr);        }  catch(NumberFormatException e1)  {      page = 1 ;  }

  try  {      Pagination.defaultPerPage = Integer.parseInt(perPageStr);   perPage = Pagination.defaultPerPage ;  }  catch(NumberFormatException e1)  {   perPage = Pagination.defaultPerPage ;     }      session = HibernateSessionFactory.getSession();  //HibernateSessionFactory是myeclipse给你封装好的一个类。    //我们要的是记录的总数目，在HQL中，select count(*) from User  //就是选出记录数，但是怎么用Criteria来实现选出记录数呢？

  //关系表的三种操作：选取（选行）、连接、投影（选列）  session.beginTransaction() ;  Criteria criteria = session.createCriteria(clazz)           .setProjection(Projections.rowCount());  //这就得到了记录数  Integer rowCount = (Integer) criteria.uniqueResult();  int totalPage = (rowCount.intValue()+perPage-1)/perPage ;//总页数    if(page<1 || page>totalPage)  {   page = 1 ;  }

  result = session.createCriteria(clazz).setFirstResult((page-1)*perPage)             .setMaxResults(perPage)             .list() ;   session.getTransaction().commit();      request.setAttribute(Pagination.PAGE,new Integer(page));//当前页数  request.setAttribute(Pagination.TOTAL_PAGE,new Integer(totalPage));  //总页数存入请求作用域

  HibernateSessionFactory.closeSession() ;  //不仅关闭了Session，还把ThreadLocal中清空了，这里不能使用Session.close()  return result ;

 }}

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前台封装：

显示分页的结果：

第1页/共10页  上一页   下一页    跳转到__页  每页6条

应该封装成标签较好。

建一个标签处理类：

package org.mybbs.taglib;

public class PaginationTag extends SimpleTagSupport{ private String url = null ;

 private boolean showPerPage = true ; private boolean showToPage = true ; //别忘了给上面的三个属性加入getter和setter方法！！！  public void doTag() throws JspException,IOException {  PageContext pageContext = (PageContext)getJspContext ;  JspWriter out = pageContext.getOut() ;  StringBuffer sb = new StringBuffer() ;  if(url==null)  {   url = ((HttpServletRequest)pageContext.getRequest()).getRequestURI();  }  System.out.println(url);    sb.append("<form action='")    .append(url)    .append("'>");

  renderInfo(pageContext,sb); //第1页/共10页  renderPrePage(pageContext,sb);//上一页          renderNextPage(pageContext,sb);//下一页  if(showToPage) renderToPage(sb);// 跳转到__页  if(showPerPage) renderPerPage(sb);//每页6条    sb.append("</form>");  out.println(sb.toString()); }

 protected void renderInfo(PageContext pageContext,StringBuffer sb)   throws JspException,IOException {    Integer page = (Integer)pageContext.getRequest().getAttribute(Pagination.PAGE);  if(page==null)  {   page = new Integer(1) ;   }  Integer totalPage = (Integer)pageContext.getRequest()   .getAttribute(Pagination.TOTAL_PAGE);

  sb.append("第")    .append(page.intValue())    .append("页");  if(totalPage!=null)  {   sb.append("/").append("共").append(totalPage).append(页);  } }

 protected void renderPrePage(PageContext pageContext,StringBuffer sb)   throws JspException,IOException {  Integer page = (Integer)pageContext.getRequest().getAttribute(Pagination.PAGE);  if(page==null)  {   page = new Integer(1) ;   }

  if(page.intValue()<=0)  {   sb.append("    ").append("上一页");  }  else  {   sb.append("<a href='").append(url).append("?").append(Pagination.PAGE)     .append("=").append(page.intValue()-1)     .append("'>").append("上一页").append("</a>");  } }

 protected void renderNextPage(PageContext pageContext,StringBuffer sb)   throws JspException,IOException {  Integer page = (Integer)pageContext.getRequest().getAttribute(Pagination.PAGE);  if(page==null)  {   page = new Integer(0) ;   }    Integer totalPage = (Integer)pageContext.getRequest()   .getAttribute(Pagination.TOTAL_PAGE);    if(totalPage==null)  {   return ;   }  if(page.intValue()>=totalPage.intValue())  {   sb.append("    ").append("下一页");  }  else  {   sb.append("<a href='").append(url).append("?").append(Pagination.PAGE)     .append("=").append(page.intValue()+1)     .append("'>").append("下一页").append("</a>");  } }

 protected void renderToPage(StringBuffer sb) throws JspException,IOException {  sb.append("到<input type='text' name='")    .append(Pagination.PAGE)    .append("' size='1' οnblur='document.forms[0].submit()'>页");     }

 protected void renderPerPage(StringBuffer sb) throws JspException,IOException {  sb.append("每页显示<input type='text' name='")    .append(Pagination.PER_PAGE)    .append("' size='1' οnblur='document.forms[0].submit()'>条");     }}

建立一个tld文件mybbs.tld

<tlib-version>2.0</tlib-version><short-name>mybbs</shourt-name>

<tag> <name>pagination</name> <tag-class>org.mybbs.taglib.PaginationTag</tag-class> <body-content>scriptless</body-content> <attribute>  <name>url</name>  <required>no</required>  <rtexprvalue>yes</rtpextvalue> </attribute> <attribute>  <name>showToPage</name>  <required>no</required>  <rtexprvalue>yes</rtpextvalue> </attribute> <attribute>  <name>showPerPage</name>  <required>no</required>  <rtexprvalue>yes</rtpextvalue> </attribute></tag>

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做一个Action来测试一下上面的分页封装：org.mybbs.action.GeneralActioni作为Action的直接父类

<action path="/listSection" type="org.mybbs.action.ListSectionAction"> <forward name="success" path="/WEB-INF/jsp/listSection.jsp"></action>public class ListSectionAction extends GeneralAction{ public ActionForward execute() {  request.setAttribute("sections",query(request,Sections.class,true));  return mapping.findForward("success"); }}

在WEB-INF中建立一个jsp页面listSection.jsp

引入mybbs的tld文件和logic的tld文件。

<body> <table border="1">  <logic:iterate id="section" name="sections">   <tr>    <td>${section.sectionId}</td>    <td>${section.sectionName}</td>    <td>${section.sectionEnglishName}</td>    <td>${section.sectionTable}</td>    <td>${section.onlineAmount}</td>    <td>${section.sectionCreateTime}</td>   </tr>  </logic:iterate>  <tr>   <td colspan="6" align="right">    <mybbs:pagination url="${pageContext.request.contextPath}/listSection.do"/>   </td>  </tr> </table></body>