Spring MVC 自定义验证

2025年3月17日 | 阅读 3 分钟

Spring MVC 框架允许我们执行自定义验证。在这种情况下，我们声明自己的注解。我们可以根据自己的业务逻辑执行验证。

Spring MVC 自定义验证示例

在此示例中，我们同时使用预定义的注解和自定义注解来验证用户输入。

1. 将依赖项添加到 pom.xml 文件。

pom.xml

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.1.1.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jasper</artifactId>
    <version>9.0.12</version>
</dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>  
    <groupId>javax.servlet</groupId>  
    <artifactId>servlet-api</artifactId>  
    <version>3.0-alpha-1</version>  
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>
 <!-- https://mvnrepository.com/artifact/org.hibernate.validator/hibernate-validator -->
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.13.Final</version>
</dependency>

2. 创建 bean 类

Employee.java

package com.javatpoint;

import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import com.javatpoint.customvalidation.Password;

public class Employee {
	private String name;
	//Custom annotation
	@Password
	private String password;
	//Predefined annotation
	@Min(value=18, message="must be equal or greater than 18")
	@Max(value=45, message="must be equal or less than 45")
	private int age;

	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 int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}	
}

3. 创建控制器类

EmployeeController.java

 package com.javatpoint;

import javax.validation.Valid;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class EmployeeController {
	
	@RequestMapping("/hello")
	public String showForm(Model theModel) {
		
		theModel.addAttribute("emp", new Employee());
		
		return "viewpage";
	}
	
	@RequestMapping("/helloagain")
	public String processForm(
			@Valid @ModelAttribute("emp") Employee emp,
			BindingResult br) {
				
		if (br.hasErrors()) {
			return "viewpage";
		}
		else {
			return "final";
		}
	}
}

4. 创建验证器注解

Password.java

package com.javatpoint.customvalidation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

@Constraint(validatedBy = PasswordConstraintValidator.class)
@Target( { ElementType.METHOD, ElementType.FIELD } )
@Retention(RetentionPolicy.RUNTIME)
public @interface Password {
	//error message
		public String message() default "must contain jtp";
	//represents group of constraints	
		public Class<?>[] groups() default {};
	//represents additional information about annotation
		public Class<? extends Payload>[] payload() default {};
}

5. 创建验证器类

PasswordConstraintValidator.java

package com.javatpoint.customvalidation;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class PasswordConstraintValidator implements ConstraintValidator<Password,String> {

	public boolean isValid(String s, ConstraintValidatorContext cvc) {
		
		boolean result=s.contains("jtp");
		return result;
	}
}

6. 在 web.xml 文件中提供控制器的条目

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>SpringMVC</display-name>
   <servlet>  
    <servlet-name>spring</servlet-name>  
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  
    <load-on-startup>1</load-on-startup>    
</servlet>  
<servlet-mapping>  
    <servlet-name>spring</servlet-name>  
    <url-pattern>/</url-pattern>  
</servlet-mapping>  
</web-app>

7. 在 xml 文件中定义 bean

spring-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="
		http://www.springframework.org/schema/beans
    	http://www.springframework.org/schema/beans/spring-beans.xsd
    	http://www.springframework.org/schema/context
    	http://www.springframework.org/schema/context/spring-context.xsd
    	http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
	<!-- Provide support for component scanning -->
	<context:component-scan base-package="com.javatpoint" />
	<!--Provide support for conversion, formatting and validation -->
	<mvc:annotation-driven/>
	<!-- Define Spring MVC view resolver -->
     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"></property>
        <property name="suffix" value=".jsp"></property>     
     </bean>
</beans>

8. 创建请求的页面

index.jsp

<html>
<body>
<a href="hello">Click here...</a>
</body>
</html>

9. 创建其他视图组件

viewpage.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
	<style>
		.error {color:red}
	</style>
</head>
<body>
	<form:form action="helloagain" modelAttribute="emp">
		Username: <form:input path="name" />		
		<br><br>
		
		Password (*): <form:password path="password" />
		<form:errors path="password" cssClass="error" />
		<br><br>
		
		Age (*): <form:input path="age" />
		<form:errors path="age" cssClass="error" />
		<br><br>
		<input type="submit" value="Submit" />
	</form:form>
</body>
</html>

final.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<body>
Username: ${emp.name}<br><br>
Password: ${emp.password}<br><br>
Age: ${emp.age}
<br><br>
</body>
</html>

输出