springboot实战笔记(十二)----springboot常见表单数据校验

小鱼儿 2022-01-25 19:07 212阅读 0赞

### 一 创建模拟用户注册项目 ###

pom.xml文件:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.10.RELEASE</version>
    	</parent>
    	<groupId>com.bjsxt</groupId>
    	<artifactId>13-spring-boot-validate</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    
    	<properties>
    		<java.version>1.7</java.version>
    		<thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>
    		<thymeleaf-layout-dialect.version>2.0.4</thymeleaf-layout-dialect.version>
    	</properties>
    
    	<dependencies>
    		
    		<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>
    	</dependencies>
    </project>

### 二 创建实体类 ###

package com.bjsxt.pojo;
    
    import javax.validation.constraints.Min;
    
    import org.hibernate.validator.constraints.Email;
    import org.hibernate.validator.constraints.Length;
    import org.hibernate.validator.constraints.NotBlank;
    import org.hibernate.validator.constraints.NotEmpty;
    
    public class Users {
    	@NotBlank(message="用户名不能为空") //非空校验 判断字符串是否为 null 或者是空串(去掉首尾空格)。
    	@Length(min=2,max=6,message="最小长度为2位,最大长度为6位")
    	private String name;
    	@NotEmpty//非空校验  判断字符串是否 null 或者是空串
    	private String password;
    	@Min(value=15)
    	private Integer age;
    	@Email(message="邮箱不合法")
    	private String email;
    	
    	public String getEmail() {
    		return email;
    	}
    	public void setEmail(String email) {
    		this.email = email;
    	}
    	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 Integer getAge() {
    		return age;
    	}
    	public void setAge(Integer age) {
    		this.age = age;
    	}
    	@Override
    	public String toString() {
    		return "Users [name=" + name + ", password=" + password + ", age=" + age + "]";
    	}
    	
    }

### 三 创建Controller ###

/**
     * SpringBoot 表单数据校验
     *
     *
     */
    @Controller
    public class UsersController {
    	/**
    	 * 
    	 * 如果想为传递的对象更改名称，可以使用@ModelAttribute("u")这表示当前传递的对象的key为aa。
    	 * 那么我们在页面中获取该对象的key也需要修改为u
    	 * @param users
    	 * @return
    	 */
    	@RequestMapping("/addUser")
    	public String showPage(@ModelAttribute("u") Users users){
    		return "add";
    	}
    	
    	/**
    	 * 完成用户添加
    	 *@Valid 开启对Users对象的数据校验
    	 *BindingResult:封装了校验的结果
    	 */
    	@RequestMapping("/save")
    	public String saveUser(@ModelAttribute("u") @Valid Users users,BindingResult result){
    		if(result.hasErrors()){
    			return "add";
    		}
    		System.out.println(users);
    		return "success";
    	}
    }

### 四 创建html ###

add.html

<!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>添加用户</title>
    </head>
    <body>
    	<form th:action="@{/save}" method="post">
    		用户姓名：<input type="text" name="name"/><font color="red" th:errors="${u.name}"></font><br/>
    		用户密码：<input type="password" name="password" /><font color="red" th:errors="${u.password}"></font><br/>
    		用户年龄：<input type="text" name="age" /><font color="red" th:errors="${u.age}"></font><br/>
    		用户邮箱：<input type="text" name="email" /><font color="red" th:errors="${u.email}"></font><br/>
    		<input type="submit" value="注册"/>
    	</form>
    </body>
    </html>

success.html

<!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>操作成功</title>
    </head>
    <body>
    	注册成功！！！
    </body>
    </html>

### 五 创建启动类测试 ###

package com.bjsxt;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class App {
    
    	public static void main(String[] args) {
    		SpringApplication.run(App.class, args);
    	}
    
    }

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### 六 总结 ###

**错误重现**

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在测试过程中可能会出现以下错误：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMjIzMjk5_size_16_color_FFFFFF_t_70 3][]

解决办法：

*  将变量名改为类名的首字母小写，例如Users变量名为users
 *  利用@ModelAttribute("u")自定义变量

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