Spring中WebDataBinder使用詳解

更新時間：2017年07月05日 10:06:07 作者：無名小卒升級中

這篇文章主要為大家詳細介紹了Spring中WebDataBinder的使用，具有一定的參考價值，感興趣的小伙伴們可以參考一下

Spring MVC Validator @InitBinder and WebDataBinder;Validator是一個用來我們自定義驗證的sping接口,WebDataBinder 綁定你的自定義參數(shù),你直接在你的控制器類中通過@InitBinder 注解的方式配置 Web 數(shù)據(jù)綁定.registerCustomEditor()是一個屬性編輯器,比如自定義的日期編輯它綁定web請求參數(shù)到JavaBean的屬性;

下面一個例子,我們創(chuàng)建一個JavaBean(username, password, email and date of birth of a user),我們創(chuàng)建兩個自定義的驗證類.第一個,我們驗證用戶名和密碼.第二個,驗證郵箱,

在Eclipse中Demo的結構

Validator 是一個有兩個方法的接口;

boolean supports(Class<?> clazz) : 檢驗參數(shù)是否驗證成功的實例類;

void validate(Object target, Errors errors) : 如果 supports() 方法返回真, target object 合法. Errors.rejectValue() 方法用一個字段名注冊錯誤信息;

UserValidator.java

package com.concretepage.validators;
import org.springframework.stereotype.Component;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import com.concretepage.User;
@Component
public class UserValidator implements Validator {
  @Override
  public boolean supports(Class<?> clazz) {
    return User.class.isAssignableFrom(clazz);
  }
  @Override
  public void validate(Object target, Errors errors) {
    User user = (User)target;
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "","Username is empty");
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "", "Password is empty");
    if (user.getName().length()<5) {
      errors.rejectValue("name","", "Username length is less than 5");
    }
  }
}

EmailValidator.java

package com.concretepage.validators;
import org.springframework.stereotype.Component;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import com.concretepage.User;
@Component
public class EmailValidator implements Validator {
  @Override
  public boolean supports(Class<?> clazz) {
    return User.class.isAssignableFrom(clazz);
  }
  @Override
  public void validate(Object target, Errors errors) {
    User user = (User)target;
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "email", "","Email is empty");
    if (!user.getEmail().contains("@")) {
      errors.rejectValue("email","", "Email is not valid.");
    }
  }
}

User.java

package com.concretepage;
import java.util.Date;
public class User {
  private String name;
  private String password;
  private String email;
  private Date dob;
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public String getPassword() {
    return password;
  }
  public void setPassword(String password) {
    this.password = password;
  }
  public String getEmail() {
    return email;
  }
  public void setEmail(String email) {
    this.email = email;
  }
  public Date getDob() {
    return dob;
  }
  public void setDob(Date dob) {
    this.dob = dob;
  }
}

MyWorldController

package com.concretepage;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.propertyeditors.CustomDateEditor;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
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;

import com.concretepage.validators.EmailValidator;
import com.concretepage.validators.UserValidator;
@Controller
@RequestMapping("/myworld")
public class MyWorldController {
  @Autowired
  private UserValidator userValidator;
  @Autowired
  private EmailValidator emailValidator;

  @RequestMapping(value="signup", method = RequestMethod.GET)
  public ModelAndView user(){
    return new ModelAndView("user","user",new User());
  }
  @InitBinder
  public void dataBinding(WebDataBinder binder) {
    binder.addValidators(userValidator, emailValidator);
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");
    dateFormat.setLenient(false);
    binder.registerCustomEditor(Date.class, "dob", new CustomDateEditor(dateFormat, true));
  }
  
  @RequestMapping(value="save", method = RequestMethod.POST)
  public String createUser(@ModelAttribute("user") @Valid User user,BindingResult result, ModelMap model) {
    if(result.hasErrors()) {
      return "user";
    }
    System.out.println("Name:"+ user.getName());
    System.out.println("Email:"+ user.getEmail());
    System.out.println("Date of Birth:"+ user.getDob());
    model.addAttribute("msg", "Welcome to My World!");
    return "success";
  }  
}

Form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>

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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