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Spring中WebDataBinder使用详解

2019年07月22日  | 移动技术网IT编程  | 我要评论

spring mvc validator @initbinder and webdatabinder;validator是一个用来我们自定义验证的sping接口,webdatabinder 绑定你的自定义参数,你直接在你的控制器类中通过@initbinder 注解的方式配置 web 数据绑定.registercustomeditor()是一个属性编辑器,比如自定义的日期编辑它绑定web请求参数到javabean的属性;

下面一个例子,我们创建一个javabean(username, password, email and date of birth of a user),我们创建两个自定义的验证类.第一个,我们验证用户名和密码.第二个,验证邮箱,

在eclipse中demo的结构


validator 是一个有两个方法的接口;

boolean supports(class<?> clazz) : 检验参数是否验证成功的实例类;

void validate(object target, errors errors) : 如果 supports() 方法返回真,  target object 合法. errors.rejectvalue() 方法用一个字段名注册错误信息;

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页面表单

<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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