spring mvc 参数类型转换

实现方式以字符串转Date为例说明:

全局配置

第一种:实现 Converter 接口

• 实现类: 
  public class StringToDateConveter implements Converter {

  private String formatPatten;
  
      public StringToDateConveter(String formatPatten){
          this.formatPatten=formatPatten;
      }
  
      @Override
      public Date convert(String s) {
          return DateUtil.string2Date(s,formatPatten);
      }
  }

• mvc.xml配置

  <mvc:annotation-driven conversion-service="conversionService"></mvc:annotation-driven>
  
  <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
      <property name="converters">
          <set>
              <bean class="com.lannong.api.www.converter.StringToDateConveter">
                  <constructor-arg name="formatPatten" value="yyyy-MM-dd"/>
              </bean>
          </set>
      </property>
  </bean>

• 配置到handlerAdapter

  <!--使用 ConfigurableWebBindingInitializer 注册conversionService-->
     <bean id="webBindingInitializer" class="org.springframework.web.bind.support.ConfigurableWebBindingInitializer">
          <property name="conversionService" ref="conversionService"/>
     </bean>
  
     <!-- 注册ConfigurableWebBindingInitializer 到RequestMappingHandlerAdapter-->
     <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
          <property name="webBindingInitializer" ref="webBindingInitializer"/>
     </bean>

第二种:实现Formatter接口,与第一种实现方式相似

• 实现类

  public class MyDateFormater implements Formatter<Date> {
  
      @Override
      public Date parse(String s, Locale locale) throws ParseException {
          return DateTimeUtil.string2Date(s,"yyyy-MM-dd");
      }
  
      @Override
      public String print(Date date, Locale locale) {
          return null;
      }
  }

• mvc.xml配置

  <mvc:annotation-driven conversion-service="conversionService"></mvc:annotation-driven>
  
  <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
      <property name="formatters">
          <set>
              <bean class="com.lannong.api.www.converter.MyDateFormater"/>
          </set>
      </property>
  </bean>

第三种:实现WebBindingInitializer接口

• 实现类

  public class MyWebBindingInitializer implements WebBindingInitializer {
  
      @Override
      public void initBinder(WebDataBinder binder, WebRequest request) {
  
          binder.registerCustomEditor(Date.class, new PropertyEditorSupport() {
              @Override
              public void setAsText(String text) {
                  setValue(DateTimeUtil.string2Date(text, "yyyy-MM-dd"));
              }
          });
      }
  }

• mvc.xml配置

  <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
      <property name="webBindingInitializer">
          <bean class="com.lannong.api.www.binder.MyWebBindingInitializer"/>
      </property>
      <!-- others config -->
  </bean>

局部配置

在Controller中添加转换方法并添加@InitBinder

• 代码

  @InitBinder
  public void initBinder(WebDataBinder webDataBinder) throws Exception{
      SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm");
      simpleDateFormat.setLenient(false);
      webDataBinder.registerCustomEditor(Date.class , new CustomDateEditor(simpleDateFormat , true));
  }
  
  或
  
  @InitBinder
  public void initBinder(WebDataBinder binder, WebRequest request) {
      binder.registerCustomEditor(Date.class, new PropertyEditorSupport() {
          @Override
          public void setAsText(String text) {
              setValue(DateTimeUtil.string2Date(text, "yyyy-MM-dd"));
          }
      });
  }

两种方式均可以,做用域和该方法做用域同样

使用@DateTimeFormat(pattern = "yyyy-MM-dd")

注解能够加在属性上,也能够加在方法上,须要导入joda-time.jar。另外日期参数的格式须要和patten定义的一致,不然会报400错误