做学生登录信息必填项验证。
student信息有：id,姓名，年龄
Student.java
public class Student {
private Integer id;
private Integer age;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
StudentValidator.java数据验证代码
import org.springframework.stereotype.Service;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
@Service
public class StudentValidator implements Validator
{
public boolean supports(Class<?> clazz){
return Student.class.isAssignableFrom(clazz);
}
public void validate(Object target, Errors errors) {
ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "required.name","Field name is required.");
}
}
注意：StudentValidator 需要加@Service注解，否则自动装载会报错，找不到bean
自动注入的时候，找不到对应的bean
原因是：对应要注入的实现类没有 加注解，如dao层 @Repository 如service层 @Service
StudentController.java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.web.servlet.ModelAndView;
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.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.Validator;
import org.springframework.validation.annotation.Validated;
@Controller
public class StudentController {
@Autowired
@Qualifier("studentValidator")
private Validator validator;
@InitBinder
private void initBinder(WebDataBinder binder) {
binder.setValidator(validator);
}
//前端from数据引用:commandName
@ModelAttribute("student")
public Student createStudentModel() {
return new Student();
}
@RequestMapping(value = "/student", method = RequestMethod.GET)
public ModelAndView student() {
return new ModelAndView("student", "command", new Student());
}
@RequestMapping(value = "/addStudent", method = RequestMethod.POST)
public String addStudent(@ModelAttribute("student") @Validated Student student,
BindingResult bindingResult, Model model) {
if (bindingResult.hasErrors()) {
return "student";
}
model.addAttribute("name", student.getName());
model.addAttribute("age", student.getAge());
model.addAttribute("id", student.getId());
return "student_result";
}
}
下面来看看jsp代码
student.jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Spring MVC表单处理</title>
</head>
<style>
.error {
color: #ff0000;
}
.errorStyle {
color: #000;
background-color: #ffEEEE;
border: 3px solid #ff0000;
padding: 8px;
margin: 16px;
}
</style>
<body>
<h2>学生信息</h2>
<form:form method="POST" action="/hello/addStudent" commandName="student">
<form:errors path="*" cssClass="errorStyle" element="div" />
<table>
<tr>
<td><form:label path="name">姓名：</form:label></td>
<td><form:input path="name" /></td>
<td><form:errors path="name" cssClass="error" /></td>
</tr>
<tr>
<td><form:label path="age">年龄：</form:label></td>
<td><form:input path="age" /></td>
</tr>
<tr>
<td><form:label path="id">编号：</form:label></td>
<td><form:input path="id" /></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="提交" /></td>
</tr>
</table>
</form:form>
</body>
</html>
这一块的代码：<form:form method="POST" action="/hello/addStudent" commandName="student">，其中commandName中的student是,studentController中的createStudentModel的定义.
这一块的代码：<form:errors path="*" cssClass="errorStyle" element="div" />，cssClass为样式代码,element元素为div.
student_result.jsp
<%@ page contentType="text/html; charset=UTF-8" %>
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ page isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>spring mvc表单处理</title>
</head>
<body>
<h2>提交的学生信息</h2>
<table>
<tr>
<td>名称:</td>
<td>${name}</td>
</tr>
<tr>
<td>年龄:</td>
<td>${age}</td>
</tr>
<tr>
<td>编号:</td>
<td>${id}</td>
</tr>
</table>
</body>
</html>