Struts2的常用三大技术:
1、数据回显
2、模型驱动
3、防止表单重复提交
一、数据回显:
1、数据回显,必须要用struts标签!
2、代码讲解:
1)Action:
// 进入修改页面
public String viewUpdate() {
// 模拟一个对象(先获取一个id,再根据id调用service查询,把查到的结果保存到域)
User userInfo = new User();
userInfo.setUserName("Endeavor");
userInfo.setEmail("[email protected]");
ActionContext ac = ActionContext.getContext();
// Map<String,Object> request = (Map<String, Object>) ac.get("request");
// request.put("userInfo", userInfo);
/************* 数据回显***************/
// 获取值栈
ValueStack vs = ac.getValueStack();
vs.pop();// 移除栈顶元素
vs.push(userInfo); // 入栈
// 进入修改页面
return "viewUpdate";
}
2)jsp页面:
<body>
<%@taglib uri="/struts-tags" prefix="s" %>
<br/>
<!-- 在页面文本框内,显示要修改记录的数据 -->
<!-- 手动通过value设置显示的值
<s:form action="#">
用户名: <s:textfield name="user.userName" value="%{#request.userInfo.userName}"></s:textfield> <br/>
邮箱: <s:textfield name="user.email" value="%{#request.userInfo.email}"></s:textfield> <br/>
</s:form>
-->
<!-- 数据回显技术:s:textfield会自动查找根元素数据(Ognl表达式语言取值) -->
<s:form action="#">
用户名: <s:textfield name="userName"></s:textfield> <br/>
邮箱: <s:textfield name="email"></s:textfield> <br/>
</s:form>
<s:debug></s:debug>
</body>
二、防止表单重复提交
核心:Struts提供了防止表单重复提交拦截器:
<interceptor name="token"
class="org.apache.struts2.interceptor.TokenInterceptor"/>
通过案例进行说明:
1、update.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Add</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
</head>
<body>
<s:form action="/emp_update" method="post">
<!-- 隐藏域,保存主键 -->
<s:hidden name="id"></s:hidden>
<table>
<tr>
<td>员工名:</td>
<td><s:textfield name="empName" /></td>
</tr>
<tr>
<td>日期:</td>
<!--
<td><s:date name="workDate" format="yyyy-MM-dd"/>
<s:hidden name="workDate"></s:hidden>
</td>
-->
<td>
<s:textfield name="workDate" />
</td>
</tr>
<tr>
<td colspan="2">
<s:submit value="修改员工"></s:submit>
</td>
</tr>
</table>
</s:form>
</body>
</html>
2、list.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>list</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
</head>
<body>
<table border="1" align="center">
<tr>
<th>序号</th>
<th>编号</th>
<th>员工名称</th>
<th>日志日期</th>
<th>操作</th>
</tr>
<!-- 1. 先判断;2. 再迭代 -->
<s:if test="#request.listEmp != null">
<s:iterator var="emp" value="#request.listEmp" status="st">
<tr>
<td><s:property value="#st.count"/></td>
<td><s:property value="#emp.id"/></td>
<td><s:property value="#emp.empName"/></td>
<td><s:property value="#emp.workDate"/></td>
<td>
<s:a href="emp_viewUpdate?id=%{#emp.id}">修改</s:a>
</td>
</tr>
</s:iterator>
</s:if>
<s:else>
<tr>
<td colspan="5">对不起,没有你要显示的数据</td>
</tr>
</s:else>
</table>
</body>
</html>
3、add.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Add</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
</head>
<body>
<s:form action="/emp_save" method="post">
<!-- 防止表单重复提交,第一步:生成id(客户端、服务器) -->
<s:token></s:token>
<table>
<tr>
<td>员工名:</td>
<td><s:textfield name="empName" /></td>
</tr>
<tr>
<td>日期:</td>
<td><s:textfield name="workDate" /></td>
</tr>
<tr>
<td colspan="2">
<s:submit value="保存员工"></s:submit>
</td>
</tr>
</table>
</s:form>
</body>
</html>
4、EmployeeAction.java
public class EmployeeAction extends ActionSupport implements ModelDriven<Employee>{
/****封装数据****/
private Employee employee = new Employee();
public Employee getEmployee() {
return employee;
}
public void setEmployee(Employee employee) {
this.employee = employee;
}
// 重写模型驱动方法
@Override
public Employee getModel() {
return employee;
}
/****调用的Service****/
private IEmployeeService employeeService = new EmployeeService();
/**
* 1. 添加员工
*/
public String save() {
try {
// 调用service保存
employeeService.save(employee);
// 添加成功,去到列表页面
return list();
//return "addsuccess";
} catch (Exception e) {
e.printStackTrace();
return ERROR;
}
}
/**
* 2. 列表显示
*/
public String list() {
try {
// 查询全部
List<Employee> listEmp = employeeService.getAll();
// 保存到request域
ActionContext.getContext().getContextMap().put("listEmp", listEmp);
return "list";
} catch (Exception e) {
e.printStackTrace();
return ERROR;
}
}
/**
* 3. 进入修改页面
*/
public String viewUpdate() {
try {
// 3.1 获取当前修改的记录的主键值
int id = employee.getId();
// 3.2 service查询
Employee emp = employeeService.findById(id);
// 3.3 数据回显
// a. 先得到值栈
ValueStack vs = ActionContext.getContext().getValueStack();
vs.pop(); //移除栈顶元素
vs.push(emp); // emp对象放入栈顶
return "update";
} catch (Exception e) {
e.printStackTrace();
return ERROR;
}
}
/**
* 4. 修改员工
*/
public String update() {
try {
// 调用service修改
employeeService.update(employee);
return list();
} catch (Exception e) {
e.printStackTrace();
return ERROR;
}
}
}
5、struts.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<!-- 更改主题 -->
<constant name="struts.ui.theme" value="simple"></constant>
<package name="emp" extends="struts-default">
<!-- 全局视图 -->
<global-results>
<result name="error">/error/error.jsp</result>
</global-results>
<action name="emp_*" class="cn.itcast.action.EmployeeAction" method="{1}">
<!-- 防止表单重复提交,第二步: 配置" 防止表单重复提交拦截器" -->
<interceptor-ref name="defaultStack"></interceptor-ref>
<interceptor-ref name="token">
<!-- 指定拦截哪些方法需要防止表单重复提交(save) -->
<param name="includeMethods">save</param>
</interceptor-ref>
<!-- 防止表单重复提交,第三步: 如果用户重复提交了跳转到指定的错误页面 -->
<result name="invalid.token" type="redirectAction">emp_list</result>
<!-- 首页显示 -->
<result name="list">/WEB-INF/list.jsp</result>
<!-- 进入修改页面 -->
<result name="update">/WEB-INF/update.jsp</result>
<!--
<result name="addsuccess" type="redirectAction">emp_list</result>
-->
</action>
</package>
</struts>