以下示例说明如何使用Spring Web MVC Framework在表单中使用错误处理和验证程序.首先,让我们使用一个可用的Eclipse IDE,并考虑以下步骤,使用Spring Web Framework开发基于动态表单的Web应用程序.
Step | 描述 |
---|---|
1 | 在com.it1352包下创建一个名为HelloWeb的项目,如Spring MVC中所述 - Hello World章节. |
2 | 在com下创建Java类Student,StudentController和StudentValidator .it1352包. |
3 | 创建视图文件addStudent.jsp, jsp子文件夹下的result.jsp. |
4 | 决赛步骤是创建源和配置文件的内容并导出应用程序,如下所述. |
package com.it1352; public class Student { private Integer age; 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.validation.Errors; import org.springframework.validation.ValidationUtils; import org.springframework.validation.Validator; public class StudentValidator implements Validator { @Override public boolean supports(Class<?> clazz) { return Student.class.isAssignableFrom(clazz); } @Override public void validate(Object target, Errors errors) { ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "required.name","Field name is required."); } }
package com.it1352; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.validation.BindingResult; import org.springframework.validation.Validator; import org.springframework.validation.annotation.Validated; import org.springframework.web.bind.WebDataBinder; import org.springframework.web.bind.annotation.InitBinder; 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 { @Autowired @Qualifier("studentValidator") private Validator validator; @InitBinder private void initBinder(WebDataBinder binder) { binder.setValidator(validator); } @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"; } }
<beans xmlns = "http://www.springframework.org/schema/beans" xmlns:context = "http://www.springframework.org/schema/context" 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"> <context:component-scan base-package = "com.IT屋" /> <bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name = "prefix" value = "/WEB-INF/jsp/" /> <property name = "suffix" value = ".jsp" /> </bean> <bean id = "studentValidator" class = "com.IT屋.StudentValidator" /> </beans>
这里,对于第一个服务方法 student(),我们在ModelAndView对象中传递了一个名为"command"的空白Studentobject ",因为spring框架需要一个名为"command"的对象,如果你使用< 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 addStudent()将在 HelloWeb/addStudent URL上调用POST方法.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 = "/HelloWeb/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> </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>
这里我们使用带有path ="*"的< form:errors/> 标记来呈现错误消息.例如
<form:errors path = "*" cssClass = "errorblock" element = "div" />
它将呈现所有输入验证的错误消息.
我们正在使用< form:带有path ="name"的errors/> 标记,用于呈现名称字段的错误消息.例如
<form:errors path = "name" cssClass = "error" />
它将呈现名称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/HelloWeb/addStudent 如果Spring Web Application的一切正常,我们将看到以下屏幕.
提交所需信息后,单击"提交"按钮提交表单.如果Spring Web Application的一切正常,你应该看到以下屏幕.