SpringMVC - 数据绑定（自定义数据转换器：PropertyEditor、Formatter、Converter）（三）

1、PropertyEditor：内置可扩展，在类中进行局部使用 webdatabinder。（不推荐，一般使用全局方案会比较多）
2、Formatter：内置可扩展，全局，或者使用new Formatter的方式进行局部使用，只能转换String到其他类型。
3、Converter：内置不可扩展，全局或局部，和Formatter类似，但Converter的源对象不仅仅是String，而可以自行进行定义。

一、PropertyEditor

@RequestMapping(value = "date1.do")
@ResponseBody
public String date1(Date date1){
    return date1.toString();
}

@InitBinder("date1")
public void initDate1(WebDataBinder binder){
    binder.registerCustomEditor(Date.class,new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"),true));
}

二、Formatter

package com.imooc.common;

import org.springframework.format.Formatter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class MyDateFormatter implements Formatter<Date> {

    public Date parse(String text, Locale locale) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        return sdf.parse(text);
    }

    public String print(Date object, Locale locale) {
        return null;
    }
}

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:aop="http://www.springframework.org/schema/aop"
       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">

    <context:component-scan base-package="com" annotation-config="true"/>
    <mvc:annotation-driven conversion-service="myDateFormatter"/>

    <bean id ="myDateFormatter" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
        <property name="formatters">
            <set>
                <bean class="com.imooc.common.MyDateFormatter"></bean>
            </set>
        </property>
    </bean>

</beans>

@RequestMapping(value = "date2.do")
@ResponseBody
public String date2(Date date2){
    return date2.toString();
}

三、Converter

package com.imooc.common;

import org.springframework.core.convert.converter.Converter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MyDateConverter implements Converter<String,Date> {

    public Date convert(String source) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            return sdf.parse(source);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }
}

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:aop="http://www.springframework.org/schema/aop"
       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">

    <context:component-scan base-package="com" annotation-config="true"/>
    <mvc:annotation-driven conversion-service="myDateConverter"/>

    <bean id ="myDateConverter" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="com.imooc.common.MyDateConverter"></bean>
                <bean class="org.springframework.core.convert.support.StringToBooleanConverter"></bean>
            </set>
        </property>
    </bean>

</beans>

@RequestMapping(value = "date2.do")
@ResponseBody
public String date2(Date date2){
    return date2.toString();
}