spring mvc 使用jsr-303進行表單驗證的方法介紹

源代碼來源：http://howtodoinjava.com/spring/spring-mvc/spring-bean-validation-example-with-jsr-303-annotations/，原文解釋的更加清楚。此文主要是爲了理順整個項目的構建過程。

採用JSR303來進行FORM驗證，JSR-303實體驗證的主要目的是經過註解對JAVA實體進行標準化驗證。其主要目標是直接在java實體類中使用註解。即經過註釋將須要驗證的代碼直接使用相應的驗證規則進行驗證，這樣則不須要從新創建驗證規則的類型。其中主要是使用了JSR-303標準。

首先先看下項目的結構。

首先，建立maven項目，而後修改其結構發佈到tomcat服務器中。

2.經過maven，引入須要的jar包，pom.xml文件以下：

<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>
  <groupId>com.howtodoinjava.mvc</groupId>
  <artifactId>jsr303Demo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  
 <dependencies>
   <dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>1.0.0.GA</version>
  </dependency>
  <dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>4.3.1.Final</version>
  </dependency>
  <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
 
        <!-- Spring MVC support -->
 
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>
 
        <!-- Tag libs support for view layer -->
 
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
            <scope>runtime</scope>
        </dependency>
 
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
            <scope>runtime</scope>
        </dependency>
</dependencies>
</project>

　　

 

3. 在model中添加驗證準則

package com.howtodoinjava.demo.model;

import java.io.Serializable;

import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;

public class EmployeeVO implements Serializable 
{
    private static final long serialVersionUID = 1L;
 
    private Integer id;
     
   
@Size(min = 3, max = 20)
    private String firstName;
     
    @Size(min = 3, max = 20)
    private String lastName;
     
    @Pattern(regexp=".+@.+\\.[a-z]+")
    private String email;
 
    //Setters and Getters
    public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

public String getEmail() {
return email;
}

public void setEmail(String email) {
this.email = email;
}

    @Override
    public String toString() {
        return "EmployeeVO [id=" + id + ", firstName=" + firstName
                + ", lastName=" + lastName + ", email=" + email + "]";
    }
}

　　

 

4.配置web.xml以及spring-servlet.xml文件（spring調度器）

--- web.xml文件

<web-app id="WebApp_ID" version="2.4"
    xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
     
    <display-name>Spring Web MVC Hello World Application</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>

　　

 

--- spring-servlet.xml文件

<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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd">
 
    <context:component-scan base-package="com.howtodoinjava.demo" />
 
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
    <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
     
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/" />
        <property name="suffix" value=".jsp" />
    </bean>
     
    <bean  class="org.springframework.context.support.ResourceBundleMessageSource">
        <property name="basename" value="messages" />
    </bean>
     
</beans>

　　

紅色部分爲經過配置文件配置解析器（disolver）。因此須要在WEB-INF文件下創建messages.properties文件，spring會自動去識別messages開頭的文件。其內容以下：

lbl.page=Add New Employee

lbl.firstName=First Name

lbl.lastName=Last Name

lbl.email=Email Id

 

5. 編寫controller，建立EmployeeController.class，具體代碼以下:

package com.howtodoinjava.demo.controller;
 
import java.util.Set;
 
import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
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.bind.annotation.SessionAttributes;
import org.springframework.web.bind.support.SessionStatus;
 
import com.howtodoinjava.demo.model.EmployeeVO;
import com.howtodoinjava.demo.service.EmployeeManager;
 
@Controller
@RequestMapping("/employee-module/addNew")
@SessionAttributes("employee")
public class EmployeeController {
    @Autowired
    EmployeeManager manager;
 
    private Validator validator;
 
    public EmployeeController()
    {
        ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
        validator = validatorFactory.getValidator();
    }
 
    @RequestMapping(method = RequestMethod.GET)
    public String setupForm(Model model) {
        EmployeeVO employeeVO = new EmployeeVO();
        model.addAttribute("employee", employeeVO);
        return "addEmployee";
    }
 
    @RequestMapping(method = RequestMethod.POST)
    public String submitForm(@ModelAttribute("employee") EmployeeVO employeeVO,
            BindingResult result, SessionStatus status) {
 
        Set<ConstraintViolation<EmployeeVO>> violations = validator.validate(employeeVO);
         
        for (ConstraintViolation<EmployeeVO> violation : violations)
        {
            String propertyPath = violation.getPropertyPath().toString();
            String message = violation.getMessage();
            // Add JSR-303 errors to BindingResult
            // This allows Spring to display them in view via a FieldError
            result.addError(new FieldError("employee",propertyPath,
 
                                   "Invalid "+ propertyPath + "(" + message + ")"));
        }
 
        if (result.hasErrors()) {
            return "addEmployee";
        }
        // Store the employee information in database
        // manager.createNewRecord(employeeVO);
 
        // Mark Session Complete
        status.setComplete();
        return "redirect:addNew/success";
    }
 
    @RequestMapping(value = "/success", method = RequestMethod.GET)
    public String success(Model model) {
        return "addSuccess";
    }
}

　　

 

5.建立view，一個addEmployee.jsp和一個addSuccess.jsp，分別以下：

--- addEmployee.jsp文件

<%@ page contentType="text/html;charset=UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags" %>
 
<html>
<head>
    <title>Add Employee Form</title>
</head>
 
<body>
    <h2><spring:message code="lbl.page" text="Add New Employee" /></h2>
    <br/>
    <form:form method="post" modelAttribute="employee">
        <table>
            <tr>
                <td><spring:message code="lbl.firstName" text="First Name" /></td>
                <td><form:input path="firstName" /></td>
                <td><form:errors path="firstName" cssClass="error" /></td>
            </tr>
            <tr>
                <td><spring:message code="lbl.lastName" text="Last Name" /></td>
                <td><form:input path="lastName" /></td>
                <td><form:errors path="lastName" cssClass="error" /></td>
            </tr>
            <tr>
                <td><spring:message code="lbl.email" text="Email Id" /></td>
                <td><form:input path="email" /></td>
                <td><form:errors path="email" cssClass="error" /></td>
            </tr>
            <tr>
                <td colspan="3"><input type="submit" value="Add Employee"/></td>
            </tr>
        </table>
    </form:form>
</body>
</html>
 

　　

--- addSuccess.jsp文件

<html>
    <head>
        <title>Add Employee Success</title>
    </head>
    <body>
        Employee has been added successfully.
    </body>
</html>

　　

 

到此使用JSR-303驗證表單數據的例子就結束了。經過url =  http://localhost:8080/jsr303Demo/employee-module/addNew進行訪問，則

點擊Add Employee按鈕，當輸入數據不符合驗證規則時，則會顯示錯誤信息。