2022-08-20  阅读(482)

Spring MVC默认情况下可以对基本类型进行类型转换,例如可以将String转换为Integer,Double,Float等。但是Spring MVC并不能转换日期类型(java.util.Date),如果希望把字符串参数转换为日期类型,必须自定义类型转换器。接下来讲解如何自定义类型转换器。

1 设计表单

            
            <%@ page contentType="text/html;charset=UTF-8" language="java" %>
            <html>
            <head>
                <title>一点教程网 - www.yiidian.com</title>
            </head>
            <body>
            <h2>自定义类型转换</h2>
            <form action="/param.do" method="post">
                用户名:<input type="text" name="username"><br>
                生日:<input type="text" name="birthday"><br>
                <input type="submit" value="提交">
            </form>
            </body>
            </html>

2 设计Pojo

User对象:

            
            package com.yiidian.domain;
            
            import java.util.Date;
            import java.util.List;
            import java.util.Map;
            
            /**
             * 用于封装表单数据
             * 一点教程网 - www.yiidian.com
             */
            public class User {
                private String username;
                private Date birthday;//这里接收的是java.util.Date类型
            
                public String getUsername() {
                    return username;
                }
            
                public void setUsername(String username) {
                    this.username = username;
                }
            
                public Date getBirthday() {
                    return birthday;
                }
            
                public void setBirthday(Date birthday) {
                    this.birthday = birthday;
                }
            
                @Override
                public String toString() {
                    return "User{" +
                            "username='" + username + '\'' +
                            ", birthday=" + birthday +
                            '}';
                }
            }

3 编写日期类型转换器

            
            package com.yiidian.converter;
            import org.springframework.core.convert.converter.Converter;
            import java.text.ParseException;
            import java.text.SimpleDateFormat;
            import java.util.Date;
            /**
             * 字符串转换日期类型转换器
             * 一点教程网 - www.yiidian.com
             */
            public class StringToDateConverter implements Converter<String,Date>{
                @Override
                public Date convert(String source) {
                    Date date = null;
                    try {
                        //使用SimpleDateFormat对页面字符串日期转换为java.util.Date类型
                        date = new SimpleDateFormat("yyyy-MM-dd").parse(source);
                    } catch (ParseException e) {
                        e.printStackTrace();
                    }
                    return date;
                }
            }

注意:Spring MVC的自定义类型转换器必须实现Converter接口

4 配置自定义类型转换器

            
            <?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: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/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
            
                <!-- 1.扫描Controller的包-->
                <context:component-scan base-package="com.yiidian.controller"/>
            
                <!-- 2.配置视图解析器 -->
                <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
                    <!-- 2.1 页面前缀 -->
                    <property name="prefix" value="/pages/"/>
                    <!-- 2.2 页面后缀 -->
                    <property name="suffix" value=".jsp"/>
                </bean>
            
                <!-- 3.创建处理器适配器和处理器映射器-->
                <mvc:annotation-driven conversion-service="conversionService"/>
            
                <!--4.配置自定义类型转换器-->
                <!--4.1 创建类型转换器对象-->
                <bean id="stringToDateConverter" class="com.yiidian.converter.StringToDateConverter"/>
            
                <!--4.2 把新建的类型转换器对象加入到工厂中-->
                <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
                    <property name="converters">
                        <set>
                            <ref bean="stringToDateConverter"/>
                        </set>
                    </property>
                </bean>
            </beans>

5 编写Controller

            
            package com.yiidian.controller;
            import com.yiidian.domain.User;
            import org.springframework.stereotype.Controller;
            import org.springframework.web.bind.annotation.RequestMapping;
            
            import java.util.Map;
            
            /**
             * 自定义类型转换
             * 一点教程网 - www.yiidian.com
             */
            @Controller
            public class ParamController {
            
                @RequestMapping("/param.do")
                public String save(User user){
                    System.out.println("用户名:"+user.getUsername());
                    System.out.println("生日:"+user.getBirthday());
                    return "success";
                }
            }

6 运行测试

202202131334457181.png

控制台输出:

202202131334463142.png

源码下载:https://pan.baidu.com/s/1XuJrg2O1KJ3Oyp_oLkXb7A

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