spring mvc驗(yàn)證

spring mvc驗(yàn)證用于限制用戶提供的輸入。為了驗(yàn)證用戶的輸入，spring 4或更高版本支持并使用bean驗(yàn)證api。它可以同時(shí)驗(yàn)證服務(wù)器端和客戶端應(yīng)用程序。

bean驗(yàn)證api

bean驗(yàn)證api是一種java規(guī)范，可用于應(yīng)用通過(guò)注釋對(duì)對(duì)象模型的約束。在這里，我們可以驗(yàn)證長(zhǎng)度，數(shù)字，正則表達(dá)式等。除此之外，我們還可以提供自定義驗(yàn)證。

由于bean驗(yàn)證api只是一個(gè)規(guī)范，因此需要實(shí)現(xiàn)。因此，為此，它使用了hibernate validator。 hibernate validator是完全兼容的jsr-303/309實(shí)現(xiàn)，允許表達(dá)和驗(yàn)證應(yīng)用程序約束。

驗(yàn)證注釋

讓我們看看一些常用的驗(yàn)證注釋。

spring mvc驗(yàn)證示例

在此示例中，我們創(chuàng)建了一個(gè)包含輸入字段的簡(jiǎn)單表單。在此，(*)表示必須輸入相應(yīng)的字段。否則，表格會(huì)產(chǎn)生錯(cuò)誤。

1、將依賴項(xiàng)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、創(chuàng)建bean類

employee.java

package com.yapf;
import javax.validation.constraints.size;
public class employee {
  private string name;
  @size(min=1,message="required")
  private string pass;
  
  public string getname() {
    return name;
  }
  public void setname(string name) {
    this.name = name;
  }
  public string getpass() {
    return pass;
  }
  public void setpass(string pass) {
    this.pass = pass;
  } 
}

3、創(chuàng)建控制器類

在控制器類中:

• @有效注釋將驗(yàn)證規(guī)則應(yīng)用于所提供的對(duì)象。
• bindingresult 接口包含驗(yàn)證結(jié)果。

package com.yapf;
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 display(model m)
  {
    m.addattribute("emp", new employee());
    return "viewpage";
  }
  @requestmapping("/helloagain")
  public string submitform( @valid @modelattribute("emp") employee e, bindingresult br)
  {
    if(br.haserrors())
    {
      return "viewpage";
    }
    else
    {
    return "final";
    }
  }
}

4、在web.xml文件中提供控制器的條目

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>

5、在xml文件中定義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.yapf" />
  <!--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>

6、創(chuàng)建請(qǐng)求的頁(yè)面

index.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<body>
<a href="hello">click here...</a>
</body>
</html>

7、創(chuàng)建其他視圖組件

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="pass"/>  
<form:errors path="pass" cssclass="error"/><br><br>
<input type="submit" value="submit">
</form:form>
</body>
</html>

final.jsp

<html>
<body>
username: ${emp.name} <br><br>
password: ${emp.pass}
</body>
</html>

輸出:

讓我們提交表單而不輸入密碼。

現(xiàn)在，我們輸入密碼，然后提交表格。