package xxxx;
import xxxx;
import xxxx;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;
public class MySortList<E> {
/**
* 对列表中的数据按指定字段进行排序。要求类必须有相关的方法返回字符串、整型、日期等值以进行比较。
* @param list
* @param method
* @param reverseFlag
*/
public void sortByMethod(List<E> list, final String method,
final boolean reverseFlag) {
Collections.sort(list, new Comparator<Object>() {
@SuppressWarnings("unchecked")
public int compare(Object arg1, Object arg2) {
int result = 0;
try {
Method m1 = ((E) arg1).getClass().getMethod(method, null);
Method m2 = ((E) arg2).getClass().getMethod(method, null);
Object obj1 = m1.invoke(((E)arg1), null);
Object obj2 = m2.invoke(((E)arg2), null);
if(obj1 instanceof String) {
// 字符串
result = obj1.toString().compareTo(obj2.toString());
}else if(obj1 instanceof Date) {
// 日期
long l = ((Date)obj1).getTime() - ((Date)obj2).getTime();
if(l > 0) {
result = 1;
}else if(l < 0) {
result = -1;
}else {
result = 0;
}
}else if(obj1 instanceof Integer) {
// 整型(Method的返回参数可以是int的,因为JDK1.5之后,Integer与int可以自动转换了)
result = (Integer)obj1 - (Integer)obj2;
}else {
// 目前尚不支持的对象,直接转换为String,然后比较,后果未知
result = obj1.toString().compareTo(obj2.toString());
System.err.println("MySortList.sortByMethod方法接受到不可识别的对象类型,转换为字符串后比较返回...");
}
if (reverseFlag) {
// 倒序
result = -result;
}
} catch (NoSuchMethodException nsme) {
nsme.printStackTrace();
} catch (IllegalAccessException iae) {
iae.printStackTrace();
} catch (InvocationTargetException ite) {
ite.printStackTrace();
}
return result;
}
});
}
// 测试函数
public static void main(String[] args) throws Exception {
List<SkyDevOrg> skyDevOrgList = new ArrayList<>();
SkyDevOrg skydevUser1 = new SkyDevOrg();
skydevUser1.setCode("B0100007");
skydevUser1.setName("公司10");
SkyDevOrg skydevUser2 = new SkyDevOrg();
skydevUser2.setCode("B0100008");
skydevUser2.setName("公司8");
SkyDevOrg skydevUser3 = new SkyDevOrg();
skydevUser3.setCode("B0100006");
skydevUser3.setName("公司3");
SkyDevOrg skydevUser4 = new SkyDevOrg();
skydevUser4.setCode("B0100005");
skydevUser4.setName("公司4");
SkyDevOrg skydevUser5 = new SkyDevOrg();
skydevUser5.setCode("B0100004");
skydevUser5.setName("公司1");
SkyDevOrg skydevUser6 = new SkyDevOrg();
skydevUser6.setCode("B0100003");
skydevUser6.setName("公司2");
skyDevOrgList.add(skydevUser1);
skyDevOrgList.add(skydevUser2);
skyDevOrgList.add(skydevUser3);
skyDevOrgList.add(skydevUser4);
skyDevOrgList.add(skydevUser5);
skyDevOrgList.add(skydevUser6);
// 方式二排序输出
MySortList<SkyDevOrg> msList = new MySortList<SkyDevOrg>();
msList.sortByMethod(skyDevOrgList, "getCode", false);
for(SkyDevOrg skyDevOrg:skyDevOrgList){
System.out.println(skyDevOrg.getCode()+","+skyDevOrg.getName());
}
}
}
Java: Collection, a method to sort custom objects in a list (List) according to attributes (fields) (positive order, reverse order)
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Origin blog.csdn.net/wujian_csdn_csdn/article/details/112274134
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