以下示例显示如何使用Spring Web MVC框架在表单中使用错误处理和验证器.首先,让我们使用一个有效的Eclipse IDE,并遵循以下步骤,使用Spring Web Framework开发基于动态表单的Web应用程序.
Step | 描述 |
---|---|
1 | 在包com下创建名为 TestWeb 的项目.it1352在Spring MVC中解释 - Hello World章节. |
2 | 在com.it1352包下创建Java类Student,StudentController和StudentValidator. |
3 | 在jsp子文件夹下创建视图文件addStudent.jsp和result.jsp. |
4 | 下载Hibernate Validator库 Hibernate Validator .解压缩hibernate-validator-5.3.4.Final.jar以及下载的zip文件所需文件夹下的必需依赖项.把它们放在你的CLASSPATH中. |
5 | 创建SRC文件夹下的属性文件messages.properties. |
6 | 最后一步是创建源文件和配置文件的内容并导出应用程序,如下所述. |
package com.it1352; import org.hibernate.validator.constraints.NotEmpty; import org.hibernate.validator.constraints.Range; public class Student { @Range(min = 1, max = 150) private Integer age; @NotEmpty private String name; private Integer id; public void setAge(Integer age) { this.age = age; } public Integer getAge() { return age; } public void setName(String name) { this.name = name; } public String getName() { return name; } public void setId(Integer id) { this.id = id; } public Integer getId() { return id; } }
package com.it1352; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.validation.BindingResult; import org.springframework.validation.annotation.Validated; import org.springframework.web.bind.annotation.ModelAttribute; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.servlet.ModelAndView; @Controller public class StudentController { @RequestMapping(value = "/addStudent", method = RequestMethod.GET) public ModelAndView student() { return new ModelAndView("addStudent", "command", new Student()); } @ModelAttribute("student") public Student createStudentModel() { return new Student(); } @RequestMapping(value = "/addStudent", method = RequestMethod.POST) public String addStudent(@ModelAttribute("student") @Validated Student student, BindingResult bindingResult, Model model) { if (bindingResult.hasErrors()) { return "addStudent"; } model.addAttribute("name", student.getName()); model.addAttribute("age", student.getAge()); model.addAttribute("id", student.getId()); return "result"; } }
NotEmpty.student.name = Name is required! Range.student.age = Age value must be between 1 and 150!
此处,密钥为< Annotation>.< object-name>.< attribute>.值是要显示的消息.
<beans xmlns = "http://www.springframework.org/schema/beans" xmlns:context = "http://www.springframework.org/schema/context" xmlns:mvc = "http://www.springframework.org/schema/mvc" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation = " http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <context:component-scan base-package = "com.IT屋" /> <mvc:annotation-driven /> <bean class = "org.springframework.context.support.ResourceBundleMessageSource" id = "messageSource"> <property name = "basename" value = "messages" /> </bean> <bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name = "prefix" value = "/WEB-INF/jsp/" /> <property name = "suffix" value = ".jsp" /> </bean> </beans>
这里,对于第一个服务方法 student(),我们已经传递了空白 Studentobject> 在名为"command"的ModelAndView对象中,因为spring框架需要名为"command"的对象,如果您使用的是< form:form> JSP文件中的标记.因此,当调用 student()方法时,它返回 addStudent.jsp 视图.
第二种服务方法将对 HelloWeb/addStudent URL上的POST方法调用addStudent().您将根据提交的信息准备模型对象.最后,将从service方法返回"result"视图,这将导致呈现result.jsp.如果使用验证器生成错误,则返回相同的视图"addStudent",Spring会自动从 BindingResult 中注入错误消息.
<%@taglib uri = "http://www.springframework.org/tags/form" prefix = "form"%> <html> <head> <title>Spring MVC Form Handling</title> </head> <style> .error { color: #ff0000; } .errorblock { color: #000; background-color: #ffEEEE; border: 3px solid #ff0000; padding: 8px; margin: 16px; } </style> <body> <h2>Student Information</h2> <form:form method = "POST" action = "/TestWeb/addStudent" commandName = "student"> <form:errors path = "*" cssClass = "errorblock" element = "div" /> <table> <tr> <td><form:label path = "name">Name</form:label></td> <td><form:input path = "name" /></td> <td><form:errors path = "name" cssClass = "error" /></td> </tr> <tr> <td><form:label path = "age">Age</form:label></td> <td><form:input path = "age" /></td> <td><form:errors path = "age" cssClass = "error" /></td> </tr> <tr> <td><form:label path = "id">id</form:label></td> <td><form:input path = "id" /></td> </tr> <tr> <td colspan = "2"> <input type = "submit" value = "Submit"/> </td> </tr> </table> </form:form> </body> </html>
在这里,我们使用< form:errors/>用path ="*"标记以呈现错误消息.例如 :
<form:errors path = "*" cssClass = "errorblock" element = "div" />
它将为所有输入验证呈现错误消息.我们正在使用< form:errors/>标记为path ="name"以呈现名称字段的错误消息.
例如 :
<form:errors path = "name" cssClass = "error" /> <form:errors path = "age" cssClass = "error" />
它将呈现名称和年龄字段验证的错误消息.
<%@taglib uri = "http://www.springframework.org/tags/form" prefix = "form"%> <html> <head> <title>Spring MVC Form Handling</title> </head> <body> <h2>Submitted Student Information</h2> <table> <tr> <td>Name</td> <td>${name}</td> </tr> <tr> <td>Age</td> <td>${age}</td> </tr> <tr> <td>ID</td> <td>${id}</td> </tr> </table> </body> </html>
完成创建源文件和配置文件后,导出应用程序.右键单击您的应用程序,使用 Export → WAR文件选项并将 HelloWeb.war 文件保存在Tomcat的webapps文件夹中.
现在,启动Tomcat服务器并确保您能够使用标准浏览器从webapps文件夹访问其他网页.尝试一下URL : http://localhost:8080/TestWeb/addStudent 如果您输入了无效值,我们将看到以下屏幕.