springMVC 类型转换

一、使用注解式控制器注册PropertyEditor(针对具体的controller类处理)

1、使用WebDataBinder进行控制器级别的注册PropertyEditor(控制器独享)

 

@InitBinder// 此处的参数也可以是ServletRequestDataBinder类型public void initBinder(WebDataBinder binder) throws Exception {// 注册自定义的属性编辑器// 1、日期DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//CustomDateEditor类是系统内部自带的类CustomDateEditor dateEditor = new CustomDateEditor(df, true);// 表示如果命令对象有Date类型的属性，将使用该属性编辑器进行类型转换binder.registerCustomEditor(Date.class, dateEditor);// 自定义的电话号码编辑器(和【4.16.1、数据类型转换】一样)binder.registerCustomEditor(PhoneNumberModel.class, new PhoneNumberEditor());}

 

 备注：转换对象必须要实现PropertyEditor接口，例如CustomDateEditor类

 

package org.springframework.beans.propertyeditors;import java.beans.PropertyEditorSupport;import java.text.DateFormat;import java.text.ParseException;import java.util.Date;import org.springframework.util.StringUtils;public class CustomDateEditor extends PropertyEditorSupport {private final DateFormat dateFormat;private final boolean allowEmpty;private final int exactDateLength;public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty) {this.dateFormat = dateFormat;this.allowEmpty = allowEmpty;exactDateLength = -1;}public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty, int exactDateLength) {this.dateFormat = dateFormat;this.allowEmpty = allowEmpty;this.exactDateLength = exactDateLength;}public void setAsText(String text) throws IllegalArgumentException {if (allowEmpty && !StringUtils.hasText(text)) {setValue(null);} else {if (text != null && exactDateLength >= 0 && text.length() != exactDateLength)throw new IllegalArgumentException((new StringBuilder("Could not parse date: it is not exactly")).append(exactDateLength).append("characters long").toString());try {setValue(dateFormat.parse(text));} catch (ParseException ex) {throw new IllegalArgumentException((new StringBuilder("Could not parse date: ")).append(ex.getMessage()).toString(), ex);}}}public String getAsText() {Date value = (Date) getValue();return value == null ? "" : dateFormat.format(value);}}

 

2、使用xml配置实现类型转换(系统全局转换器)

（1、注册ConversionService实现和自定义的类型转换器 

<!-- ①注册ConversionService --><bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean"><property name="converters">   <list><bean class="hb.base.convert.DateConverter"><constructor-arg value="yyyy-MM-dd"/></bean></list></property><!-- 格式化显示的配置<property name="formatters"><list><bean class="hb.base.convert.DateFormatter"><constructor-arg value="yyyy-MM-dd"/></bean></list></property>--></bean>

 

（2、使用 ConfigurableWebBindingInitializer 注册conversionService

<!-- ②使用 ConfigurableWebBindingInitializer 注册conversionService --><bean id="webBindingInitializer"class="org.springframework.web.bind.support.ConfigurableWebBindingInitializer"><property name="conversionService" ref="conversionService" /><property name="validator" ref="validator" /></bean>

 

（3、注册ConfigurableWebBindingInitializer 到RequestMappingHandlerAdapter

<!--Spring3.1开始的注解 HandlerAdapter --><beanclass="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"><!--线程安全的访问session --><property name="synchronizeOnSession" value="true" /><property name="webBindingInitializer" ref="webBindingInitializer"/></bean>

 

此时可能有人会问，如果我同时使用 PropertyEditor 和 ConversionService，执行顺序是什么呢？内部首先查找PropertyEditor 进行类型转换，如果没有找到相应的 PropertyEditor 再通过 ConversionService进行转换。