[置顶] java中List按照指定字段排序工具类

包括如下几个类

1. 实体类

 package com.newyear.wish;

 /**
  * 实体类
  *
  */
 public class Video {

     public Video(int id, String title, int hits) {
         super();
         this.id = id;
         this.title = title;
         this.hits = hits;
     }

     private int id;
     private String title;
     private int hits;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getTitle() {
         return title;
     }
     public void setTitle(String title) {
         this.title = title;
     }
     public int getHits() {
         return hits;
     }
     public void setHits(int hits) {
         this.hits = hits;
     }

 }

2. list排序工具类

 

 package com.newyear.wish;

 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;

 /**
  *  List按照指定字段排序工具类
  *
  * @param <T>
  */

 public class ListSortUtil<T> {
     /**
      * @param targetList 目标排序List
      * @param sortField 排序字段(实体类属性名)
      * @param sortMode 排序方式（asc or  desc）
      */
     @SuppressWarnings({ "unchecked", "rawtypes" })
     public void sort(List<T> targetList, final String sortField, final String sortMode) {

         Collections.sort(targetList, new Comparator() {
             public int compare(Object obj1, Object obj2) {
                 int retVal = 0;
                 try {
                     //首字母转大写
                     String newStr=sortField.substring(0, 1).toUpperCase()+sortField.replaceFirst("\\w","");
                     String methodStr="get"+newStr;

                     Method method1 = ((T)obj1).getClass().getMethod(methodStr, null);
                     Method method2 = ((T)obj2).getClass().getMethod(methodStr, null);
                     if (sortMode != null && "desc".equals(sortMode)) {
                         retVal = method2.invoke(((T) obj2), null).toString().compareTo(method1.invoke(((T) obj1), null).toString()); // 倒序
                     } else {
                         retVal = method1.invoke(((T) obj1), null).toString().compareTo(method2.invoke(((T) obj2), null).toString()); // 正序
                     }
                 } catch (Exception e) {
                     throw new RuntimeException();
                 }
                 return retVal;
             }
         });
     }

 }

3. 测试类

 package com.newyear.wish;

 import java.util.ArrayList;
 import java.util.List;

 public class ListSortUtilTest {

     /**
      * @param args
      */
     public static void main(String[] args) {


         List<Video> targetList = new ArrayList<Video>();
         targetList.add(new Video(1,"title1",31));
         targetList.add(new Video(2,"title2",12));
         targetList.add(new Video(3,"title3",53));
         System.out.println("排序前: " + targetList);

         ListSortUtil<Video> sortList = new ListSortUtil<Video>();
         sortList.sort(targetList, "hits", "asc");
         System.out.println("排序后：" +targetList);

     }

 }