SpringBoot非官方教程 | 第十九篇：验证表单信息

构建工程

创建一个springboot工程，由于用到了 web 、thymeleaf、validator、el，引入相应的起步依赖和依赖，代码清单如下：

    
    <dependencies> 
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-thymeleaf</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.hibernate</groupId>
    			<artifactId>hibernate-validator</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.apache.tomcat.embed</groupId>
    			<artifactId>tomcat-embed-el</artifactId>
    		</dependency>
    	</dependencies>

创建一个PresonForm的Object类

    package com.forezp.entity;
    
    import javax.validation.constraints.Min;
    import javax.validation.constraints.NotNull;
    import javax.validation.constraints.Size;
    /**
     * Created by fangzhipeng on 2017/4/19.
     */
    public class PersonForm {
    
        @NotNull
        @Size(min=2, max=30)
        private String name;
    
        @NotNull
        @Min(18)
        private Integer age;
    
        public String getName() {
            return this.name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public String toString() {
            return "Person(Name: " + this.name + ", Age: " + this.age + ")";
        }
    }

这个实体类，在2个属性:name,age.它们各自有验证的注解：

@Size(min=2, max=30) name的长度为2-30个字符
@NotNull 不为空
@Min(18)age不能小于18

创建 web Controller

    @Controller
    public class WebController extends WebMvcConfigurerAdapter {
    
        @Override
        public void addViewControllers(ViewControllerRegistry registry) {
            registry.addViewController("/results").setViewName("results");
        }
    
        @GetMapping("/")
        public String showForm(PersonForm personForm) {
            return "form";
        }
    
        @PostMapping("/")
        public String checkPersonInfo(@Valid PersonForm personForm, BindingResult bindingResult) {
    
            if (bindingResult.hasErrors()) {
                return "form";
            }
    
            return "redirect:/results";
        }
    }

创建form表单

src/main/resources/templates/form.html:

    <html>
        <body>
            <form action="#" th:action="@{/}" th:object="${personForm}" method="post">
                | Name:||NameError|
| :-----: | :-----: | :-----: | 
| Name: |  | NameError | 
| Age: |  | AgeError | 
| Submit | 

            </form>
        </body>
    </html>

注册成功的页面

src/main/resources/templates/results.html:

    
    html>
    	<body>
    		Congratulations! You are old enough to sign up for this site.
    	</body>
    </html>

演示

启动工程，访问http://localhost:8080/：

如果你输入A和15，点击 submit:

如果name 输入N, age为空：

如果输入：forezp. 18

参考资料

https://spring.io/guides/gs/validating-form-input/

源码下载

https://github.com/forezp/SpringBootLearning

阅读全文