SpringMVC--验证器应用实例（超详细）

叁歲伎倆 2021-08-13 16:22 433阅读 0赞

#### Spring MVC验证器应用实例 ####

编写一个实现 org.springframework.validation.Validator 接口的验证器类 GoodsValidator，验证要求如下：

*  商品名和商品详情不能为空。
 *  商品价格在 0 到 100。
 *  创建日期不能在系统日期之后。

**1）创建应用并导入相关JAR包**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NvbGRfX19wbGF5_size_16_color_FFFFFF_t_70]  
**2）创建数据输入页面**  
在 WEB-INF 目录下创建文件夹 jsp，并在该文件夹中创建数据输入页面 addGoods.jsp。代码如下：

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <%@taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>添加商品</title>
    </head>
    <body>
        <form:form modelAttribute="goods" action="${pageContext.request. contextPath }/goods/save" method="post">
            <fieldset>
                <legend> 添加一件商品 </legend>
                <P>
                    <label>商品名:</label>
                    <form:input path="gname" />
                </p>
                <p>
                    <label>商品详情:</label>
                    <form:input path="gdescription" />
                </p>
                <P>
                    <label>商品价格:</label>
                    <form:input path="gprice" />
                </p>
                <P>
                    <label>创建日期:</label>
                    <form:input path="gdate" />
                    (yyyy-MM-dd)
                </p>
                <p id="buttons">
                    <input id="reset" type="reset">
                    <input id="submit" type="submit" value="添加">
                </p>
            </fieldset>
            
            <form:errors path="*" />
        </form:form>
    </body>
    </html>

**3）编写模型类**  
定义领域模型类 Goods，封装输入参数。在该类中使用 @DateTimeFormat（pattern=“yyyy-MM-dd”）格式化创建日期。  
模型类 Goods 的具体代码如下：

package pers.zhang.pojo;
    
    import java.util.Date;
    
    import org.springframework.format.annotation.DateTimeFormat;
    
    public class Goods { 
        private String gname;
        private String gdescription;
        private double gprice;
        // 日期格式化（需要在配置文件中配置FormattingConversionServiceFactoryBean)
        @DateTimeFormat(pattern="yyyy-MM-dd")
        private Date gdate;
    
        public String getGname() { 
            return gname;
        }
    
        public void setGname(String gname) { 
            this.gname = gname;
        }
    
        public String getGdescription() { 
            return gdescription;
        }
    
        public void setGdescription(String gdescription) { 
            this.gdescription = gdescription;
        }
    
        public double getGprice() { 
            return gprice;
        }
    
        public void setGprice(double gprice) { 
            this.gprice = gprice;
        }
    
        public Date getGdate() { 
            return gdate;
        }
    
        public void setGdate(Date gdate) { 
            this.gdate = gdate;
        }
    }

**4）编写验证器类**  
编写实现 org.springframework.validation.Validator 接口的验证器类 GoodsValidator，使用 @Component 注解将 GoodsValidator 类声明为验证组件。具体代码如下：

package pers.zhang.validator;
    
    import java.util.Date;
    
    import org.springframework.stereotype.Component;
    import org.springframework.validation.Errors;
    import org.springframework.validation.ValidationUtils;
    import org.springframework.validation.Validator;
    
    import pers.zhang.pojo.Goods;
    
    @Component
    public class GoodsValidator implements Validator { 
        @Override
        public boolean supports(Class<?> klass) { 
            // 要验证的model,返回值为false则不验证
            return Goods.class.isAssignableFrom(klass);
        }
    
        @Override
        public void validate(Object object, Errors errors) { 
            Goods goods = (Goods) object; // object要验证的对象
            // goods.gname.required是错误消息属性文件中的编码(国际化后对应的是国际化的信息)
            ValidationUtils.rejectIfEmpty(errors, "gname", "goods. gname.required");
            ValidationUtils.rejectIfEmpty(errors, "gdescription",
                    "goods.gdescription.required");
            if (goods.getGprice() > 100 || goods.getGprice() < 0) { 
                errors.rejectValue("gprice", "gprice.invalid");
            }
            Date goodsDate = goods.getGdate();
            // 在系统时间之后
            if (goodsDate != null && goodsDate.after(new Date())) { 
                errors.rejectValue("gdate", "gdate.invalid");
            }
        }
    }

**5）编写错误消息属性文件**  
在 WEB-INF 目录下创建文件夹 resource，并在该文件夹中编写属性文件 errorMessages.properties。文件内容如下：

goods.gname.required=请输入商品名称
    goods.gdescription.required=请输入商品详情
    gprice.invalid=价格为0~100
    gdate.invalid=创建日期不能在系统日期之后

Unicode 编码（MyEclipse 带有将汉字转换成 Unicode 编码的功能）的属性文件内容如下：

goods.gname.required=\u8BF7\u8F93\u5165\u5546\u54C1\u540D\u79F0
    goods.gdescription.required=\u8BF7\u8F93\u5165\u5546\u54C1\u8BE6\u60C5
    gprice.invalid=\u4EF7\u683C\u4E3A0~100
    gdate.invalid=\u521B\u5EFA\u65E5\u671F\u4E0D\u80FD\u5728\u7CFB\u7EDF\u65E5\u671F\u4E4B\u540E

**6）编写 Service 层**  
编写一个 GoodsService 接口。具体代码如下：

package pers.zhang.service;
    
    import java.util.ArrayList;
    
    import pers.zhang.pojo.Goods;
    
    public interface GoodsService { 
        public boolean save(Goods g);
    
        public ArrayList<Goods> getGoods();
    }

GoodsServiceImpl 实现类具体代码如下：

package pers.zhang.service;
    
    import java.util.ArrayList;
    
    import org.springframework.stereotype.Service;
    
    import pers.zhang.pojo.Goods;
    
    @Service
    public class GoodsServiceImpl implements GoodsService { 
        // 使用静态集合变量goods模拟数据库
        private static ArrayList<Goods> goods = new ArrayList<Goods>();
    
        @Override
        public boolean save(Goods g) { 
            goods.add(g);
            return true;
        }
    
        @Override
        public ArrayList<Goods> getGoods() { 
            return goods;
        }
    }

**7）编写控制器类**  
编写控制器类 GoodsController，在该类中使用 @Resource 注解注入自定义验证器。另外，在控制器类中包含两个处理请求的方法，具体代码如下：

package pers.zhang.controller;
    
    import javax.annotation.Resource;
    
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    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.Validator;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    import pers.zhang.pojo.Goods;
    import pers.zhang.service.GoodsService;
    
    @Controller
    @RequestMapping("/goods")
    public class GoodsController { 
        // 得到一个用来记录日志的对象，这样在打印信息的时候能够标记打印的是哪个类的信息
        private static final Log logger = LogFactory.getLog(GoodsController.class);
        @Autowired
        private GoodsService goodsService;
        // 注解验证器相当于"GoodsValidator validator=new GoodsValidator () ; "
        @Resource
        private Validator validator;
        @RequestMapping("/input")
        public String input(Model model) { 
            // 如果model中没有goods属性，addGoods.jsp会抛出异常
            // 因为表单标签无法找到modelAttribute属性指定的form backing object
            model.addAttribute("goods", new Goods());
            return "addGoods";
        }
        @RequestMapping("/save")
        public String save(@ModelAttribute Goods goods, BindingResult result,
                Model model) { 
            this.validator.validate(goods, result); // 添加验证
            if (result.hasErrors()) { 
                return "addGoods";
            }
            goodsService.save(goods);
            logger.info("添加成功");
            model.addAttribute("goodsList", goodsService.getGoods());
            return "goodsList";
        }
    }

**8）编写配置文件**  
在 WEB-INF 目录下编写配置文件 springmvc-servlet.xml，具体代码如下：

<?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:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" 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">
            
            
        <mvc:annotation-driven/>
        
        <context:component-scan base-package="pers.zhang" />
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/WEB-INF/jsp/" />
            <property name="suffix" value=".jsp" />
        </bean>
    	
    	
        <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
        </bean>
    	
    	
    	<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        	<property name="basename" value="/WEB-INF/resource/errorMessages" />
    	</bean>
    </beans>

**9）创建数据显示页面**  
在 WEB-INF/jsp 目录下创建数据显示页面 goodsList.jsp。核心代码如下：

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
        <table>
            <tr>
                <td>商品名</td>
                <td>商品详情</td>
                <td>商品价格</td>
                <td>创建日期</td>
            </tr>
            <c:forEach items="${goodsList }" var="goods">
                <tr>
                    <td>${goods.gname }</td>
                    <td>${goods.gdescription }</td>
                    <td>${goods.gprice }</td>
                    <td>${goods.gdate }</td>
                </tr>
            </c:forEach>
        </table>
    </body>
    </html>

**10）创建 web.xml 文件**

<?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_2_5.xsd" id="WebApp_ID" version="2.5">
      <display-name>SpringMVCDemo</display-name>
      
      
        <filter>
            <filter-name>encodingFilter</filter-name>
            <filter-class>
                 org.springframework.web.filter.CharacterEncodingFilter
            </filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        </filter>
        <filter-mapping>
            <filter-name>encodingFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
        
    	
        <servlet>
    	  	<servlet-name>springmvc</servlet-name>
    	  	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    	  	
    	  	<init-param>
    	  		<param-name>contextConfigLocation</param-name>
    	  		<param-value>classpath:springmvc-servlet.xml</param-value>
    	  	</init-param>
      	</servlet>
      	<servlet-mapping>
      		<servlet-name>springmvc</servlet-name>
      		<url-pattern>/</url-pattern>
      	</servlet-mapping>
      	
      	
    </web-app>

**11）测试应用**  
启动 Tomcat 服务器，然后通过地址“http://localhost：8080/springMVCDemo08/goods/input”测试应用。

当输入价格大于 100 元时，下面会提示“价格为0~100”的信息:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NvbGRfX19wbGF5_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][20191103183448953.png]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NvbGRfX19wbGF5_size_16_color_FFFFFF_t_70]: /images/20210813/1c29f35374574c329fe930101b531f1a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NvbGRfX19wbGF5_size_16_color_FFFFFF_t_70 1]: /images/20210813/f05f5d48f50348f08ad936941e7f4f59.png
[20191103183448953.png]: /images/20210813/7edc03d9a07447fa9926522681e5c431.png