Spring高级属性

Spring属性编辑器

1. 属性编辑器是用于将传入的字符串，或数字等等转换成我们需要的属性形式。
2. Spring为我们提供了两种属性转换的方法。
   • 使用自定义属性编辑器通过继承PropertyEditorSupport，重写setAsText方法。

     /**
          * @author SeanForFun E-mail:xiaob6@mcmaster.ca
          * @date Oct 3, 2018 2:40:06 PM
          * @version 1.0
      */
     public class CustomDateFormat extends PropertyEditorSupport{
      private String format = "yyyy-MM-dd";
      public void setFormat(String format) {
       this.format = format;
      }
      @Override
      public void setAsText(String text) throws IllegalArgumentException {
       SimpleDateFormat format = new SimpleDateFormat(this.format);
       try {
           this.setValue(format.parse(text));
       } catch (ParseException e) {
           e.printStackTrace();
       }
      }
     }
     

     ```xml

   
    * 通过注册Spring自带的属性编辑器CustomDateEditor。
   ```Java
   /**
           * @author SeanForFun E-mail:xiaob6@mcmaster.ca
           * @date Oct 3, 2018 2:52:02 PM
           * @version 1.0
    */
   public class DateFormatRegister implements PropertyEditorRegistrar{
   
    @Override
    public void registerCustomEditors(PropertyEditorRegistry registry) {
        registry.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"), false));
    }
   }
   

 	<!-- 注册Spring自带编辑器, 将属性转换器注册到链表中 -->
 	<bean class="org.springframework.beans.factory.config.CustomEditorConfigurer">
 		<property name="propertyEditorRegistrars">
 			<list>
 				<bean class="com.bjsxt.spring.DatePropertyEditorRegistrar"></bean>
 			</list>
 		</property>
 	</bean>

Spring使用资源文件

使用资源文件可以将一些常量信息和bean进行隔离，以便于协同工作和整体维护。

1. 引用Properties文件
   • 通过context命名空间引用properties文件，较为简单，推荐 ```xml

   
    * 通过PropertyPlaceholderConfigurer引入文件
   ```xml
    <!-- 通过PropertyPlaceholderConfigurer引入properties文件 -->
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" scope="singleton">
    	<property name="location" value="classpath:jdbc.properties"/>
    </bean>
   

国际化i18n

国际化中最重要的是定义一个Locale对象，在构造Formater对象的时候传入我们所需要的Locale对象，通过format方法就能获得相应的国际化对象。

1. NumberFormat

   public class MyNumberFormat {
    public static void main(String[] args) {
        Locale ch = new Locale("zh", "CN");
        NumberFormat zhnf = NumberFormat.getCurrencyInstance(ch);
        Locale ca = new Locale("en", "CA");
        NumberFormat canf = NumberFormat.getCurrencyInstance(ca);
        double currency = 12345.6D;
        System.out.println(zhnf.format(currency));
        System.out.println(canf.format(currency));
    }
   }
   ￥12,345.60
   $12,345.60
   

2. MessageFormat

   /**
    * @author SeanForFun E-mail:xiaob6@mcmaster.ca
    * @date Jul 19, 2018 9:48:25 AM
    * @version 1.0
    */
   public class MyMessageFormat {
    public static void main(String[] args) {
        // 信息格式化串
        String chMsg = "{0}, 你好！你于{1}在工商银行存入{2}元！";
        String usMsg = "At {1, time, short} On {1, date,long}, {0} saved {2, number, currency}";
        // 定义动态占位符的参数
        Object[] params = {"Sean", new GregorianCalendar().getTime(), 1000000000};
        // 指定国际化信息，定义formatter
        MessageFormat zhMf = new MessageFormat(chMsg, Locale.CHINESE);
        //装配参数
        String zhPattern = zhMf.format(params);
        System.out.println(zhPattern);
        MessageFormat usMf = new MessageFormat(usMsg, Locale.CANADA);
        String usPattern = usMf.format(params);
        System.out.println(usPattern);
    }
   }
   

3. 使用ResourceBundle来存储可能被复用的国际化信息
   • 命名方式： <资源名>_<语言代码>_<国家地区代码>.properties

      greeting.common=Hello!
      greeting.morning=Good morning!
      greeting.night=Good night!
     

   • 字符串properties文件

      greeting.common=Hello {0}! Today is {1}!
      greeting.morning=Good morning {0}! Now is {1, time, short}!
      greeting.night=Good night {0}! Now is {1, date, long}!
     

   • 在程序中调用tokens和要插入的字符串

      public class MyResourceBundle {
      public static void main(String[] args) throws UnsupportedEncodingException {
       ResourceBundle enBundle = ResourceBundle.getBundle("ca/mcmaster/spring/i18n/greeting", Locale.CANADA);
       ResourceBundle cnBundle = ResourceBundle.getBundle("ca/mcmaster/spring/i18n/greeting", Locale.CHINESE);
       System.out.println(enBundle.getString("greeting.common"));
       System.out.println(new String(cnBundle.getString("greeting.common").getBytes("ISO-8859-1"), "utf-8"));
       ResourceBundle fmtBundle = ResourceBundle.getBundle("ca/mcmaster/spring/i18n/fmt_greeting", Locale.CANADA);
       MessageFormat msgFormat = new MessageFormat(fmtBundle.getString("greeting.common"), Locale.CANADA);
       Object[] params = {"Sean", new GregorianCalendar().getTime()};
       String formatMsg = msgFormat.format(params);
       System.out.println(formatMsg);
      }
     }
     

容器事件体系

Reference

1. Spring中属性编辑器的使用