Java中List根据指定字段排序工具类

测试用的业务类（必须符合JavaBean规范）：

/**
* 业务类
*
* @author andy
* @date 2016年11月15日
*/
public class ChannelSituationBean implements java.io.Serializable {

/**
*
*/
private static final long serialVersionUID = 5754354214462805574L;

private Integer id;
private Date date;
private int registCount;
private Float fee;
private float myFee;
private Double investMoney;
private double myInvestMoney;
private String registChannel;

//省略getter和setter
}

工具类

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method
4000
;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;

/**
* List根据指定字段排序
*
* @author andy
* @date 2016年11月16日
*/
public class ListSortUtil<T> {
/**
* 支持的排序字段类型：Date,String,int,Integer,double,Double,float,Float (该泛型必须符合javabean规范)
*
* @param list 要排序的集合
* @param sortField 排序字段
* @param sortRule 排序规则：(asc or desc)
*/
public void mySort(List<T> list, final String sortField, final String sortRule) {

Collections.sort(list, new Comparator<T>() {

@Override
public int compare(T o1, T o2) {
// 通过反射获取方法名称，如getId
String methodName = "get" + sortField.substring(0, 1).toUpperCase() + sortField.substring(1, sortField.length());
String flag = null;
try {
Field[] fields = o1.getClass().getDeclaredFields();
for (Field f : fields) {
if (sortField.equals(f.getName())) {
System.out.println(f.getName() + "  GenericType:  " + f.getGenericType().toString());
if (f.getGenericType().toString().equals("class java.util.Date")) {
flag = "Date";
break;
}
if (f.getGenericType().toString().equals("class java.lang.String")) {
flag = "String";
break;
}
if (f.getGenericType().toString().equals("int")) {
flag = "int";
break;
}
if (f.getGenericType().toString().equals("class java.lang.Integer")) {
flag = "Integer";
break;
}
if (f.getGenericType().toString().equals("double")) {
flag = "double";
break;
}
if (f.getGenericType().toString().equals("class java.lang.Double")) {
flag = "Double";
break;
}
if (f.getGenericType().toString().equals("float")) {
flag = "float";
break;
}
if (f.getGenericType().toString().equals("class java.lang.Float")) {
flag = "Float";
break;
}
}
}

Method method1 = o1.getClass().getMethod(methodName, null);
Method method2 = o2.getClass().getMethod(methodName, null);
// System.out.println(method1.invoke(o1, null));
// System.out.println(method2.invoke(o2, null));
if ("Date".equals(flag)) {
if ("desc".equals(sortRule)) {
return ((Date) method1.invoke(o1, null)).getTime() < ((Date) method2.invoke(o2, null)).getTime() ? 1 : -1;
} else {
return ((Date) method1.invoke(o1, null)).getTime() < ((Date) method2.invoke(o2, null)).getTime() ? -1 : 1;
}
} else if ("String".equals(flag)) {
if ("desc".equals(sortRule)) {
return method2.invoke(o2, null).toString().compareTo(method1.invoke(o1, null).toString());
} else {
System.out.println("compare result : " + method1.invoke(o1, null).toString().compareTo(method2.invoke(o2, null).toString()));
return method1.invoke(o1, null).toString().compareTo(method2.invoke(o2, null).toString());
}
} else if ("int".equals(flag) || "Integer".equals(flag)) {
if ("desc".equals(sortRule)) {
return ((Integer) method2.invoke(o2, null)).compareTo((Integer) method1.invoke(o1, null));
} else {
return ((Integer) method1.invoke(o1, null)).compareTo((Integer) method2.invoke(o2, null));
}
} else if ("double".equals(flag) || "Double".equals(flag)) {
if ("desc".equals(sortRule)) {
return ((Double) method2.invoke(o2, null)).compareTo((Double) method1.invoke(o1, null));
} else {
return ((Double) method1.invoke(o1, null)).compareTo((Double) method2.invoke(o2, null));
}
} else if ("float".equals(flag) || "Float".equals(flag)) {
if ("desc".equals(sortRule)) {
return ((Float) method1.invoke(o1, null)) < ((Float) method2.invoke(o2, null)) ? 1 : -1;
} else {
return ((Float) method1.invoke(o1, null)) < ((Float) method2.invoke(o2, null)) ? -1 : 1;
}
}
} catch (NoSuchMethodException | SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return 0;
}
});

}

public static void main(String[] args) throws ParseException {
// TODO Auto-generated method stub
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
ChannelSituationBean cs = new ChannelSituationBean();
cs.setId(1);
cs.setDate(sdf.parse("2012-10-09"));
cs.setRegistCount(15);
cs.setFee(3f);
cs.setInvestMoney(300.00);
cs.setRegistChannel("android");
cs.setMyFee(3f);
cs.setMyInvestMoney(299.99);

//
ChannelSituationBean cs1 = new ChannelSituationBean();
cs1.setId(2);
cs1.setDate(sdf.parse("2016-10-09"));
cs1.setRegistCount(8);
cs1.setFee(6f);
cs1.setInvestMoney(600.00);
cs1.setRegistChannel("android");
cs1.setMyFee(5.8f);
cs1.setMyInvestMoney(588.23);

//
ChannelSituationBean cs2 = new ChannelSituationBean();
cs2.setId(3);
cs2.setDate(sdf.parse("2014-10-09"));
cs2.setRegistCount(6);
cs2.setFee(9f);
cs2.setInvestMoney(500.05);
cs2.setRegistChannel("weixin");
cs2.setMyFee(8.88f);
cs2.setMyInvestMoney(488.00);

//
ChannelSituationBean cs3 = new ChannelSituationBean();
cs3.setId(4);
cs3.setDate(sdf.parse("2015-02-15"));
cs3.setRegistCount(10);
cs3.setFee(8f);
cs3.setInvestMoney(500.02);
cs3.setRegistChannel("ios");
cs3.setMyFee(7.99f);
cs3.setMyInvestMoney(488.99);

List<ChannelSituationBean> m_list = new ArrayList<ChannelSituationBean>();
m_list.add(cs);
m_list.add(cs1);
m_list.add(cs2);
m_list.add(cs3);

new ListSortUtil<ChannelSituationBean>().mySort(m_list, "myFee", "asc");

// Collections.sort(m_list, new Comparator<ChannelSituationBean>() {
// @Override
// public int compare(ChannelSituationBean o1, ChannelSituationBean o2) {
// return o1.getRegistCount() < o2.getRegistCount() ? 1 : -1;
// }
// });
System.out.println("--------------");
for (ChannelSituationBean csb : m_list) {
System.out.println("myFee : " + csb.getMyFee() + "----" + "myInvestMoney : " + csb.getMyInvestMoney() + "----" + sdf.format(csb.getDate()));
// System.out.println("registCount : " + csb.getRegistCount() + "----" + csb.getRegistChannel() + "----id :"
// + csb.getId());
}

}

}