SSM学习10Spring-MVC学习数据绑定02

　　5.自定义踉据绑定

Spring 框架提供了一个 Converter 用于将一种类型的对象转换为另一种类型的对象 例如， 用户输入的曰期形式可能是 "2017-04-08"或 "2017/04/08" 的字符串，而要 Spring 将输入 的日期与后台的 Date 进行绑定，则需要将字符串转换为日期，此时就可以自定义一个 Converter 类来进行曰期转换。

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新建com.zyk.convert包，新建DateConverter.java文件：

 1 package com.zyk.convert;
 2 
 3 import org.springframework.core.convert.converter.Converter;
 4 
 5 import java.text.ParseException;
 6 import java.text.SimpleDateFormat;
 7 import java.util.Date;
 8 
 9 public class DateConverter implements Converter<String,Date> {
10     private String datePattern = "yyyy-MM-dd HH:mm:ss";
11     @Override
12     public  Date convert(String source){
13         SimpleDateFormat sdf=new SimpleDateFormat(datePattern);
14         try {
15             return sdf.parse(source);
16         }catch (ParseException e){
17             throw new IllegalArgumentException("无效的日期格式，使用该格式"+datePattern);
18         }
19     }
20 }

配置applicationContext.xml文件：

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:mvc="http://www.springframework.org/schema/mvc"
 4        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5        xmlns:context="http://www.springframework.org/schema/context"
 6        xsi:schemaLocation="http://www.springframework.org/schema/beans
 7        http://www.springframework.org/schema/beans/spring-beans.xsd
 8        http://www.springframework.org/schema/context
 9        http://www.springframework.org/schema/context/spring-context.xsd
10        http://www.springframework.org/schema/mvc
11        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
12     <context:component-scan base-package="com.zyk.controller"></context:component-scan>
13     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
14         <property name="prefix" value="/WEB-INF/jsp/"></property>
15         <property name="suffix" value=".jsp"></property>
16     </bean>
17     <mvc:annotation-driven conversion-service="conversionService">
18     </mvc:annotation-driven>
19     <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
20         <property name="converters">
21             <set>
22                 <bean class="com.zyk.convert.DateConverter"></bean>
23             </set>
24         </property>
25     </bean>
26 <!--    <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">-->
27 <!--        <property name="formatters">-->
28 <!--            <set>-->
29 <!--                <bean class="com.zyk.convert.DateFormatter"></bean>-->
30 <!--            </set>-->
31 <!--        </property>-->
32 <!--    </bean>-->
33 </beans>

在com.zyk.controller中新建DateConvert

package com.zyk.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import java.util.Date;
@Controller
public class DateController {
    @RequestMapping("/customDate")
    public String customDate(Date date){
        System.out.println("date="+date);
        return "success";

    }
}

启动tomcat，输入http://localhost:8080/springMvc02_war_exploded/customDate?date=2019-4-17%2010:29:55，控制台显示了另一种时间格式，页面也跳转到了success.jsp：

　　6.Formatter

　　在com.zyk.convert包中新建DateFormatter;

 1 package com.zyk.convert;
 2 
 3 import org.springframework.format.Formatter;
 4 
 5 import java.text.ParseException;
 6 import java.text.SimpleDateFormat;
 7 import java.util.Date;
 8 import java.util.Locale;
 9 
10 public class DateFormatter  implements Formatter<Date> {
11     private String datePattern = "yyyy-MM-dd HH:mm:ss";
12     private SimpleDateFormat simpleDateFormat;
13     @Override
14     public String print(Date date , Locale locale){
15         return new SimpleDateFormat().format(date);
16     }
17     @Override
18     public Date parse(String source,Locale locale)throws ParseException{
19         simpleDateFormat=new SimpleDateFormat(datePattern);
20         return simpleDateFormat.parse(source);
21     }
22 }

修改配置文件applicationContext：

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:mvc="http://www.springframework.org/schema/mvc"
 4        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5        xmlns:context="http://www.springframework.org/schema/context"
 6        xsi:schemaLocation="http://www.springframework.org/schema/beans
 7        http://www.springframework.org/schema/beans/spring-beans.xsd
 8        http://www.springframework.org/schema/context
 9        http://www.springframework.org/schema/context/spring-context.xsd
10        http://www.springframework.org/schema/mvc
11        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
12     <context:component-scan base-package="com.zyk.controller"></context:component-scan>
13     <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
14         <property name="prefix" value="/WEB-INF/jsp/"></property>
15         <property name="suffix" value=".jsp"></property>
16     </bean>
17     <mvc:annotation-driven conversion-service="conversionService">
18     </mvc:annotation-driven>
19 <!--    <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">-->
20 <!--        <property name="converters">-->
21 <!--            <set>-->
22 <!--                <bean class="com.zyk.convert.DateConverter"></bean>-->
23 <!--            </set>-->
24 <!--        </property>-->
25 <!--    </bean>-->
26     <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
27         <property name="formatters">
28             <set>
29                 <bean class="com.zyk.convert.DateFormatter"></bean>
30             </set>
31         </property>
32     </bean>
33 </beans>

依旧时启动tomcat，输入http://localhost:8080/springMvc02_war_exploded/customDate?date=2019-4-17%2010:29:55，控制台显示了另一种时间格式，页面也跳转到了success.jsp，这里的截图一模一样就不放了。

二者区别：

　　Formatter与Converter 的作用相同，只是 Formatter 的源类型必须是一个 String 类型，而 Converter 可以是任意类型。

　　7.绑定数组

在上一个博客中创建了普通绑定的pojo--User，这里用他来演示绑定数组。

编写UserController:

package com.zyk.controller;

import com.zyk.po.User;
import com.zyk.vo.UserVO;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.List;

@Controller
public class UserController {
   
    @RequestMapping("/toUser")
    public String toUser() {
        return "user";
    }

    @RequestMapping("/deleteUser")
    public String deleteUsers(Integer[] ids) {
        if (ids != null)
            for (Integer id : ids)
                System.out.println("删除了id为" + id + "的用户！");
        else
            System.out.println("ids=null");
        return "success";
    }


}

在jsp下面新建user.jsp：

 1 <%--
 2   Created by IntelliJ IDEA.
 3   User: ZYK
 4   Date: 2019/4/17
 5   Time: 11:02
 6   To change this template use File | Settings | File Templates.
 7 --%>
 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
 9 <html>
10 <head>
11     <title>用户列表</title>
12 </head>
13 <body>
14     <form action="${pageContext.request.contextPath}/deleteUser" method="post">
15         <table border="1">
16             <tr>
17                 <td>选择</td>
18                 <td>用户名</td>
19             </tr>
20             <tr>
21                 <td><input name="ids" value="l" type="checkbox"></td>
22                 <td>tom</td>
23             </tr>
24             <tr>
25                 <td><input name="ids" value="2" type="checkbox"></td>
26                 <td>jack</td>
27             </tr>
28             <tr>
29                 <td><input name="ids" value="3" type="checkbox"></td>
30                 <td>rose</td>
31             </tr>
32         </table>
33         <input type="submit" value="删除">
34     </form>
35 </body>
36 </html>

启动tomcat，输入：http://localhost:8080/springMvc02_war_exploded/toUser，页面跳转至user.jsp：

点击删除，可以看到控制台的输出和页面跳转到success.jsp。

　　8.绑定集合

新建com.zyk.vo包，在包中新建UserVO:

package com.zyk.vo;

import com.zyk.po.User;

import java.util.List;

public class UserVO {
    private List<User> users;

    public List<User> getUsers() {
        return users;
    }

    public void setUsers(List<User> users) {
        this.users = users;
    }
}

在jsp下新建toUserEdit.jsp

 1 <%--
 2   Created by IntelliJ IDEA.
 3   User: ZYK
 4   Date: 2019/4/17
 5   Time: 18:53
 6   To change this template use File | Settings | File Templates.
 7 --%>
 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
 9 <html>
10 <head>
11     <title>修改用户</title>
12 </head>
13 <body>
14 <form action="${pageContext.request.contextPath}/editUsers" method="post" id="formid">
15     <table width="30%" border="1">
16         <tr>
17             <td>选择</td>
18             <td>用户名</td>
19         </tr>
20         <tr>
21             <td><input type="checkbox" name="users[0].id" value="1"></td>
22             <td><input type="text" name="users[0].username" value="tom"></td>
23         </tr>
24         <tr>
25             <td><input type="checkbox" name="users[1].id" value="2"></td>
26             <td><input type="text" name="users[1].username" value="jack"></td>
27         </tr>
28 
29     </table>
30     <input type="submit" value="修改">
31 </form>
32 </body>
33 </html>

UserController：　

package com.zyk.controller;

import com.zyk.po.User;
import com.zyk.vo.UserVO;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.List;

@Controller
public class UserController {
  

    @RequestMapping("/toUserEdit")
    public String toUserEdit() {
        return "toUserEdit";
    }

    @RequestMapping("/editUsers")
    public String editUsers(UserVO userVO) {
        List<User> users = userVO.getUsers();
        for (User user : users)
            if (user.getId() != null)
                System.out.println("修改id为" + user.getId() + "的用户名为" + user.getUsername());
        return "success";
    }
}

启动tomcat,浏览器输入：http://localhost:8080/springMvc02_war_exploded/toUserEdit：

点击修改后，控制台：

绑定数据中出现的问题：

1.原来为了方便把pojo中的integer类型写成了int类型，导致后面写controller类型以及从jsp传值时报错。

 

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