文章标题：java中List按照指定字段排序工具类.
文章地址: http://blog.csdn.net/5iasp/article/details/17717179
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);
}
}
测试执行结果：
排序前: [com.newyear.wish.Video@c17164, com.newyear.wish.Video@1fb8ee3, com.newyear.wish.Video@61de33]
排序后：[com.newyear.wish.Video@1fb8ee3, com.newyear.wish.Video@c17164, com.newyear.wish.Video@61de33]
