Struts 2 CRUD教程

Struts 2 CRUD教程

 

在这个例子里，我们将了解怎么执行创建，读取，升级和删除(CRUD)操作。这里只涉及到前面例子没有涉及到的内容。

 

下面是执行画面：

 

可以选择编辑和删除。

 

下面是文件路径：

 

UserDAOImpl有四种方法执行CRUD操作。

package com.vaannila.dao; import java.util.List; import org.hibernate.Session; import org.hibernate.Transaction; import com.googlecode.s2hibernate.struts2.plugin.annotations.SessionTarget; import com.googlecode.s2hibernate.struts2.plugin.annotations.TransactionTarget; import com.vaannila.domain.User; public class UserDAOImpl implements UserDAO { @SessionTarget Session session; @TransactionTarget Transaction transaction; /** * Used to save or update a user. */ @Override public void saveOrUpdateUser(User user) { try { session.saveOrUpdate(user); } catch (Exception e) { transaction.rollback(); e.printStackTrace(); } } /** * Used to delete a user. */ @Override public void deleteUser(Long userId) { try { User user = (User) session.get(User.class, userId); session.delete(user); } catch (Exception e) { transaction.rollback(); e.printStackTrace(); } } /** * Used to list all the users. */ @SuppressWarnings("unchecked") @Override public List<User> listUser() { List<User> courses = null; try { courses = session.createQuery("from User").list(); } catch (Exception e) { e.printStackTrace(); } return courses; } /** * Used to list a single user by Id. */ @Override public User listUserById(Long userId) { User user = null; try { user = (User) session.get(User.class, userId); } catch (Exception e) { e.printStackTrace(); } return user; } }

 

使用Full Hibernate Plug-in 1.4 GA注入org.hibernate.Session和org.hibernate.Transaction对象。

 

域对象(domain object)User使用JPA注释创建User表。

package com.vaannila.domain; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name="USER") public class User { private Long id; private String name; private String gender; private String country; private String aboutYou; private Boolean mailingList; @Id @GeneratedValue @Column(name="USER_ID") public Long getId() { return id; } public void setId(Long id) { this.id = id; } @Column(name="USER_NAME") public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name="USER_GENDER") public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } @Column(name="USER_COUNTRY") public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } @Column(name="USER_ABOUT_YOU") public String getAboutYou() { return aboutYou; } public void setAboutYou(String aboutYou) { this.aboutYou = aboutYou; } @Column(name="USER_MAILING_LIST") public Boolean getMailingList() { return mailingList; } public void setMailingList(Boolean mailingList) { this.mailingList = mailingList; } }

 

这里UserAction捕获ModelDriven接口，则域对象(domain object)作为模型对象(model dobject)。在动作(action)中使用ActionContext.getContext().get(ServletActionContext.HTTP_REQUEST)方法访问HttpServeletRequest。

package com.vaannila.web; import java.util.ArrayList; import java.util.List; import javax.servlet.http.HttpServletRequest; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport; import com.opensymphony.xwork2.ModelDriven; import com.vaannila.dao.UserDAO; import com.vaannila.dao.UserDAOImpl; import com.vaannila.domain.User; public class UserAction extends ActionSupport implements ModelDriven<User> { private static final long serialVersionUID = -6659925652584240539L; private User user = new User(); private List<User> userList = new ArrayList<User>(); private UserDAO userDAO = new UserDAOImpl(); @Override public User getModel() { return user; } /** * To save or update user. * @return String */ public String saveOrUpdate() { userDAO.saveOrUpdateUser(user); return SUCCESS; } /** * To list all users. * @return String */ public String list() { userList = userDAO.listUser(); return SUCCESS; } /** * To delete a user. * @return String */ public String delete() { HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get(ServletActionContext.HTTP_REQUEST); userDAO.deleteUser(Long.parseLong(request.getParameter("id"))); return SUCCESS; } /** * To list a single user by Id. * @return String */ public String edit() { HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get(ServletActionContext.HTTP_REQUEST); user = userDAO.listUserById(Long.parseLong(request.getParameter("id"))); return SUCCESS; } public User getUser() { return user; } public void setUser(User user) { this.user = user; } public List<User> getUserList() { return userList; } public void setUserList(List<User> userList) { this.userList = userList; } }

 

在struts设置中有四种不同的动作(action)分别对应不同的CRUD操作。在save，update和删除操作期间，我们需要升级user列表的显示。所以这里我们将结果(result)指定到listUser动作上。

<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <package name="default" extends="hibernate-default"> <action name="saveOrUpdateUser" method="saveOrUpdate" class="com.vaannila.web.UserAction"> <result name="success" type="redirect">listUser</result> </action> <action name="listUser" method="list" class="com.vaannila.web.UserAction"> <result name="success">/register.jsp</result> </action> <action name="editUser" method="edit" class="com.vaannila.web.UserAction"> <result name="success">/register.jsp</result> </action> <action name="deleteUser" method="delete" class="com.vaannila.web.UserAction"> <result name="success" type="redirect">listUser</result> </action> </package> </struts>

 

hibernate.cfg.xml文件内容如下：

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.connection.driver_class">org.hsqldb.jdbcDriver</property> <property name="hibernate.connection.url">jdbc:hsqldb:hsql://localhost</property> <property name="hibernate.connection.username">sa</property> <property name="connection.password"></property> <property name="connection.pool_size">1</property> <property name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</property> <property name="show_sql">true</property> <property name="hbm2ddl.auto">create</property> <mapping class="com.vaannila.domain.User" /> </session-factory> </hibernate-configuration>

 

部署描述符内容如下：

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>Struts2Example19</display-name> <filter> <filter-name>struts2</filter-name> <filter-class> org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>

 

registor.jsp页面内容如下：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <%@taglib uri="/struts-tags" prefix="s"%> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Registration Page</title> <s:head /> <mce:style type="text/css"><!-- @import url(style.css); --></mce:style><style type="text/css" mce_bogus="1">@import url(style.css);</style> </head> <body> <s:form action="saveOrUpdateUser"> <s:push value="user"> <s:hidden name="id" /> <s:textfield name="name" label="User Name" /> <s:radio name="gender" label="Gender" list="{'Male','Female'}" /> <s:select name="country" list="{'India','USA','UK'}" headerKey="" headerValue="Select" label="Select a country" /> <s:textarea name="aboutYou" label="About You" /> <s:checkbox name="mailingList" label="Would you like to join our mailing list?" /> <s:submit /> </s:push> </s:form> <s:if test="userList.size() > 0"> <div class="content"> <table class="userTable" cellpadding="5px"> <tr class="even"> <th>Name</th> <th>Gender</th> <th>Country</th> <th>About You</th> <th>Mailing List</th> <th>Edit</th> <th>Delete</th> </tr> <s:iterator value="userList" status="userStatus"> <tr class="<s:if test="#userStatus.odd == true ">odd</s:if><s:else>even</s:else>"> <td><s:property value="name" /></td> <td><s:property value="gender" /></td> <td><s:property value="country" /></td> <td><s:property value="aboutYou" /></td> <td><s:property value="mailingList" /></td> <td><s:url id="editURL" action="editUser"> <s:param name="id" value="%{id}"></s:param> </s:url> <s:a href="%{editURL}" mce_href="%{editURL}">Edit</s:a></td> <td><s:url id="deleteURL" action="deleteUser"> <s:param name="id" value="%{id}"></s:param> </s:url> <s:a href="%{deleteURL}" mce_href="%{deleteURL}">Delete</s:a></td> </tr> </s:iterator> </table> </div> </s:if> </body> </html>

 

push标签用来将对象移动到ValueStack的最顶端。在add操作期间，将用ModelDriven接口将对象以模型对象(model object)形式公开，这个阶段push标签不需要。但是在updat期间，使用listUserById()方法返回JavaBean属性的User，这个时候我们需要使用push标签。所以就不需要使用将user.name这样的二级OGNL表达式了。

public String edit() { HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get( ServletActionContext.HTTP_REQUEST); user = userDAO.listUserById(Long.parseLong(request. getParameter("id"))); return SUCCESS; }

 

url标签用来创建一个新的URL。随着URL可以使用param标签追加id值，OGNL表达式"%{}"作为转义序列在动作上下文(ActionContext)中参考值。

 

源代码：下载

源代码 + lib：下载