還是舊法矩，開門見山。 我們開發的時候常常會從html，jsp中將參數傳到後台，可是常會遇到的一種情況就是傳過來的資料到後台要組裝成一種物件的格式，最常見的就是enum類型了。這時候spring提供的@initBinder這個annotation 就發揮了很大的作用。
下面一個範例,我們建立一個JavaBean(username, password, email and date of birth of a user),我們建立兩個自訂的驗證類.第一個,我們驗證使用者名稱和密碼.第二個,驗證郵箱,
在Eclipse中Demo的結構
#Validator 是兩個方法的介面;
boolean supports( Class clazz)
: 檢定參數是否驗證成功的實例類別;
void validate(Object target, Errors errors)
: 如果
supports() 方法方法回傳真, target object 合法. Errors.rejectValue() 方法用一個欄位名稱註冊錯誤訊息;
Uservalidator.java
1 package com.concretepage.validators; 2 import org.springframework.stereotype.Component; 3 import org.springframework.validation.Errors; 4 import org.springframework.validation.ValidationUtils; 5 import org.springframework.validation.Validator; 6 import com.concretepage.User; 7 @Component 8 public class UserValidator implements Validator { 9 @Override10 public boolean supports(Class<?> clazz) {11 return User.class.isAssignableFrom(clazz);12 }13 @Override14 public void validate(Object target, Errors errors) {15 User user = (User)target;16 ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "","Username is empty");17 ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "", "Password is empty");18 if (user.getName().length()<5) {19 errors.rejectValue("name","", "Username length is less than 5");20 }21 }22 }登入後複製
UserValidator.java
EmailValidator.java
1 package com.concretepage.validators; 2 import org.springframework.stereotype.Component; 3 import org.springframework.validation.Errors; 4 import org.springframework.validation.ValidationUtils; 5 import org.springframework.validation.Validator; 6 import com.concretepage.User; 7 @Component 8 public class EmailValidator implements Validator { 9 @Override10 public boolean supports(Class<?> clazz) {11 return User.class.isAssignableFrom(clazz);12 }13 @Override14 public void validate(Object target, Errors errors) {15 User user = (User)target;16 ValidationUtils.rejectIfEmptyOrWhitespace(errors, "email", "","Email is empty");17 if (!user.getEmail().contains("@")) {18 errors.rejectValue("email","", "Email is not valid.");19 }20 }21 }登入後複製
User.java
1 package com.concretepage;
2 import java.util.Date;
3 public class User {
4 private String name;
5 private String password;
6 private String email;
7 private Date dob;
8 public String getName() {
9 return name;
10 }
11 public void setName(String name) {
12 this.name = name;
13 }
14 public String getPassword() {
15 return password;
16 }
17 public void setPassword(String password) {
18 this.password = password;
19 }
20 public String getEmail() {
21 return email;
22 }
23 public void setEmail(String email) {
24 this.email = email;
25 }
26 public Date getDob() {
27 return dob;
28 }
29 public void setDob(Date dob) {
30 this.dob = dob;
31 }
32 }登入後複製
######User.java############# #MyWorldController#####################
1 package com.concretepage; 2 import java.text.SimpleDateFormat; 3 import java.util.Date; 4 5 import javax.validation.Valid; 6 7 import org.springframework.beans.factory.annotation.Autowired; 8 import org.springframework.beans.propertyeditors.CustomDateEditor; 9 import org.springframework.stereotype.Controller;10 import org.springframework.ui.ModelMap;11 import org.springframework.validation.BindingResult;12 import org.springframework.web.bind.WebDataBinder;13 import org.springframework.web.bind.annotation.InitBinder;14 import org.springframework.web.bind.annotation.ModelAttribute;15 import org.springframework.web.bind.annotation.RequestMapping;16 import org.springframework.web.bind.annotation.RequestMethod;17 import org.springframework.web.servlet.ModelAndView;18 19 import com.concretepage.validators.EmailValidator;20 import com.concretepage.validators.UserValidator;21 @Controller22 @RequestMapping("/myworld")23 public class MyWorldController {24 @Autowired25 private UserValidator userValidator;26 @Autowired27 private EmailValidator emailValidator;28 29 @RequestMapping(value="signup", method = RequestMethod.GET)30 public ModelAndView user(){31 return new ModelAndView("user","user",new User());32 }33 @InitBinder34 public void dataBinding(WebDataBinder binder) {35 binder.addValidators(userValidator, emailValidator);36 SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");37 dateFormat.setLenient(false);38 binder.registerCustomEditor(Date.class, "dob", new CustomDateEditor(dateFormat, true));39 }40 41 @RequestMapping(value="save", method = RequestMethod.POST)42 public String createUser(@ModelAttribute("user") @Valid User user,BindingResult result, ModelMap model) {43 if(result.hasErrors()) {44 return "user";45 }46 System.out.println("Name:"+ user.getName());47 System.out.println("Email:"+ user.getEmail());48 System.out.println("Date of Birth:"+ user.getDob());49 model.addAttribute("msg", "Welcome to My World!");50 return "success";51 }
52 }登入後複製
######MyWorldController###########頁面表單###### #
<form:form action="save" method="post" commandName="user"><tr> <td>User Name:</td> <td><form:input path="name"/> </td>
<td> <form:errors path="name" cssStyle="color: red;"/></td> </tr><tr> <td> Password :</td> <td><form:input path="password"/> </td>
<td> <form:errors path="password" cssStyle="color: red;"/> </td> </tr><tr> <td> Email :</td> <td><form:input path="email"/> </td>
<td> <form:errors path="email" cssStyle="color: red;"/> </td> </tr><tr> <td> Date of Birth :</td> <td><form:input path="dob"/> </td>
<td> <form:errors path="dob" cssStyle="color: red;"/> </td> </tr> <tr> <td colspan=3> <input type="submit"> </td>
</form:form>
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