Spring Boot 2 Thymeleaf服务器端表单验证实现详解

2019-11-26 08:19:48

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这篇文章主要介绍了Spring Boot 2 Thymeleaf服务器端表单验证实现详解,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

表单验证分为前端验证和服务器端验证。

服务器端验证方面，Java提供了主要用于数据验证的JSR 303规范，而Hibernate Validator实现了JSR 303规范。

项目依赖加入spring-boot-starter-thymeleaf时，默认就会加入Hibernate Validator的依赖。

开发环境：IntelliJ IDEA 2019.2.2

Spring Boot版本：2.1.8

新建一个名称为demo的Spring Boot项目。

1、pom.xml

<dependency>      <groupId>org.springframework.boot</groupId>      <artifactId>spring-boot-starter-web</artifactId>    </dependency>    <dependency>      <groupId>org.springframework.boot</groupId>      <artifactId>spring-boot-starter-thymeleaf</artifactId>    </dependency>    <dependency>      <groupId>org.springframework.boot</groupId>      <artifactId>spring-boot-devtools</artifactId>    </dependency>

2、src/main/java/com/example/demo/User.java

package com.example.demo;import org.hibernate.validator.constraints.Length;import javax.validation.constraints.NotBlank;import javax.validation.constraints.Size;public class User {  @NotBlank(message = "用户名不能为空")  String name;  @Length(min = 11, max = 11, message = "手机号长度必须11位")  String phone;  @Size(min = 6, max = 20, message = "密码长度6-20位")  String password;  public String getName() {    return name;  }  public void setName(String name) {    this.name = name;  }  public String getPhone() {    return phone;  }  public void setPhone(String phone) {    this.phone = phone;  }  public String getPassword() {    return password;  }  public void setPassword(String password) {    this.password = password;  }}

3、src/main/java/com/example/demo/FormController.java

package com.example.demo;import org.springframework.stereotype.Controller;import org.springframework.validation.BindingResult;import org.springframework.validation.ObjectError;import org.springframework.web.bind.annotation.ModelAttribute;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestMapping;import javax.validation.Valid;import java.util.List;@Controllerpublic class FormController {  @RequestMapping("/{form}")  public String form(@PathVariable String form, @ModelAttribute User user){    return form;  }  @PostMapping("/submit")  public String submit(@Valid User user, BindingResult result){    if (result.hasErrors()) {      List<ObjectError> list = result.getAllErrors();      for (ObjectError error : list) {        System.out.println(error.getDefaultMessage());      }      return "form";    }    //业务逻辑处理    return "form";  }}

4、src/main/resources/templates/form.html

前端通过#fields对象输出错误信息有2种方式，1种是在每个字段后面输出，另1种是全部在一起输出。

<!DOCTYPE html><html><head>  <meta charset="UTF-8">  <title>表单的提交处理</title>  <style>    .fieldError{color: red}  </style></head><body>  <form method="post" th:action="@{/submit}" th:object="${user}">    <table>      <tr>        <td>用户名：</td>        <td><input type="text" th:field="*{name}" />          <span class="fieldError" th:if="${#fields.hasErrors('*{name}')}" th:errors="*{name}"></span>        </td>      </tr>      <tr>        <td>手机号：</td>        <td><input type="text" th:field="*{phone}" />          <span class="fieldError" th:if="${#fields.hasErrors('*{phone}')}" th:errors="*{phone}"></span>        </td>      </tr>      <tr>        <td>密码：</td>        <td><input type="text" th:field="*{password}" />          <span class="fieldError" th:if="${#fields.hasErrors('*{password}')}" th:errors="*{password}"></span>        </td>      </tr>      <tr>        <td colspan="2">          <input type="submit" value="提交" />          <div th:each="err : ${#fields.errors('*')}">            <span th:text="${err}" class="fieldError"></span>          </div>        </td>      </tr>    </table>  </form></body></html>

启动服务后，浏览器访问http://localhost:8080/form，点击提交按钮，结果如下：