按照指定对象的成员变量排序

有一个List<CommonDictionary>,

CommonDictionary的结构:

/**
     * 主键id
     */
    private Long id;
    /**
     * 组id
     */
    private String groupId;
    /**
     * 键<br />不能取值为key,因为key是关键字
     */
    private String key2;
    /**
     * 值
     */
    private String value;
    /**
     * 描述
     */
    private String description;

 

 

我需要对key2进行排序.

说明:

(1)key2的值是唯一的,不重复;

(2)key2的所有取值都已知.

按照什么方式排序呢?

"company_n","product_stand","production_no","registration_c","production_addr","company_web"

 排序前:

13company_name武汉市

17company_website公司网址

14product_standard产品标准aa

18production_address生产地址

15production_no生产证号

16registration_certificate_number注册证号drfdf

---------------------------------

排序后:

13company_name武汉市

14product_standard产品标准aa

15production_no生产证号

16registration_certificate_number注册证号drfdf

18production_address生产地址

17company_website公司网址

测试方法如下:

@Test
	public void tst_77(){
		List<CommonDictionary> list=DictionaryParam.getList(Constant2.DICTIONARY_GROUP_ANTICOUNTERFEIT_CODE);
		String orderTitles[]=new String[]{"company_n","product_stand","production_no","registration_c","production_addr","company_web"};
		
		for(int i=0;i<list.size();i++){
			CommonDictionary commonDictionary33=list.get(i);
			System.out.println(commonDictionary33.getId()+"\t"+commonDictionary33.getKey2()+"\t"+commonDictionary33.getValue());
		}
		
		Collections.sort(list,new SystemHWUtil. ArrayListComparator(orderTitles,"Key2"));
		System.out.println("---------------------------------");
		for(int i=0;i<list.size();i++){
			CommonDictionary commonDictionary33=list.get(i);
			System.out.println(commonDictionary33.getId()+"\t"+commonDictionary33.getKey2()+"\t"+commonDictionary33.getValue());
		}
	}

 执行结果:

 

SystemHWUtil. ArrayListComparator 实现如下:

public static class ArrayListComparator implements Comparator{
		/***
		 * 排序的依据
		 */
		private String titles[];
		/***
		 * 对哪个列进行排序
		 */
		private String comparedProperty;
		
		public ArrayListComparator(String[] titles,String comparedProperty) {
			super();
			this.titles = titles;
			this.comparedProperty=comparedProperty;
		}

		public int compare(Object o1, Object o2) {
			if(null!=o1&&null!=o2)
			{
				
				try {
					if(SystemHWUtil.indexOfArr(titles,(String)ReflectHWUtils.getObjectValue(o1, comparedProperty)   ) >
					SystemHWUtil.indexOfArr(titles,(String)ReflectHWUtils.getObjectValue(o2, comparedProperty))){
						return 1/*大于*/;
					}else {
						return -1/*小于*/;
					}
				} catch (SecurityException e) {
					e.printStackTrace();
				} catch (NoSuchFieldException e) {
					e.printStackTrace();
				} catch (IllegalArgumentException e) {
					e.printStackTrace();
				} catch (IllegalAccessException e) {
					e.printStackTrace();
				}
			}
			return 0/*等于*/;
		}
		
	}

 SystemHWUtil.indexOfArr 参考http://hw1287789687.iteye.com/blog/2145187

 

注意:

(1)titles中的元素不要有重复;

(2)ArrayListComparator 可应用于所有的Object,应该它没有与具体的类关联,而是通过反射来获取成员变量的值.

关于反射,可以参阅:http://hw1287789687.iteye.com/blog/2124280

遗留问题:

如何高效率地过滤String[]:{1,2,3,2}-->{1,2,3};

相关源码见附件