JAVA object arrays are sorted by multiple attributes __java

The following can be directly used to run, you can also download the attachment package directly, the compiler can see the effect of running directly.

//objectsort

Package sort;

Import java.util.ArrayList;
Import java.util.Collections;
Import java.util.List;

public class Objectsort {
/**
* @param args
*/
public static void Main (string[] args) {
/**
*

* Purpose: Sort by one or some of the attributes of an object
* Java contains 8 basic data types, respectively: Boolean, Byte, char, short, int, float, douboe, long
* Compare Non-Boolean and byte-type attributes, and most use environment adaptation, if there are special requirements, please modify them yourself.
* When used, simply pass the object's property list and the ordered list to
* **/
List Arraydemo = new ArrayList ();

person P1 = new person ();
P1.setname ("Zhang San");
P1.setage (22);
P1.setsalary (160);

person P2 = new person ();
P2.setname ("Zhang San");
P2.setage (22);
P2.setsalary (150);

Person P3 = new person ();
P3.setname ("Zhang San");
P3.setage (25);
P3.setsalary (1900);

person P4 = new person ();
P4.setname ("Zhao Liu");
P4.setage (25);
P4.setsalary (3000);

Person P5 = new person ();
P5.setname ("Liu Qi");
P5.setage (30);
P5.setsalary (2000);

Arraydemo.add (p1);
Arraydemo.add (p2);
Arraydemo.add (p3);
Arraydemo.add (p4);
Arraydemo.add (p5);

Start comparing ********//
Commoncomparator comparator = new Commoncomparator ();
System.out.println ("1.sort by name, age and Salary");
Comparator.setfields_user (New string[]{"name", "Age", "salary"});
Collections.sort (Arraydemo, comparator);
for (int i=0;i<arraydemo.size (); i++)
{
person who = (person) arraydemo.get (i);
System.out.println ("Name:" +person.getname () + "Age:" +person.getage () + "Salary:" +person.getsalary ());
}

System.out.println ("1.sort by name, age");
Comparator.setfields_user (New string[]{"name", "Age"});
Collections.sort (Arraydemo, comparator);
for (int i=0;i<arraydemo.size (); i++)
{
person who = (person) arraydemo.get (i);
System.out.println ("Name:" +person.getname () + "Age:" +person.getage () + "Salary:" +person.getsalary ());
}
}

}

//commoncomparator

Package sort;

Import Java.lang.reflect.Method;
Import Java.math.BigDecimal;
Import Java.text.CollationKey;
Import Java.text.Collator;
Import Java.util.Comparator;

public class Commoncomparator implements Comparator {

/***
* @param
* The properties of the comparison object are passed in the form of string[]
* The object of comparison must conform to JavaBean, that is to have Set,get method
* */
string[] Fields_user = null;


Public string[] Getfields_user () {
return fields_user;
}
public void Setfields_user (string[] fields_user) {
This.fields_user = Fields_user;
}
/**
* Define Collation
* If you are sorting by more than one attribute
* This is sorted according to the order of the attributes, which are SQL orders by
* That is, just compare the properties of the same position to stop
* */
public int Compare (object Obj1, Object obj2)
{
No attributes, no sorting
if (Fields_user = null | | fields_user.length<=0)
{
return 2;//not compare
}
for (int i=0;i<fields_user.length;i++)
{
Return Comparefield (Obj1,obj2,fields_user[i]);
if (Comparefield (Obj1,obj2,fields_user[i]) >0)
{//If Obj1 property value is greater than Obj2 property value, returns a positive number
return 1;
}else if (Comparefield (obj1,obj2,fields_user[i)) <0) {
return-1;
}
}
return 0;
}
/**
* @param fieldName
* Sorted by attribute name
* */
private static int Comparefield (Object o1,object o2,string fieldName)
{
Try
{
Object value1 = Getfieldvaluebyname (FIELDNAME,O1);
Object value2 = Getfieldvaluebyname (FIELDNAME,O2);

--string comparison
if (value1 instanceof String)
{
String v1 = getfieldvaluebyname (fieldname,o1). toString ();
String v2 = getfieldvaluebyname (FIELDNAME,O2). toString ();
Collator mycollator = Collator.getinstance ();
Collationkey[] keys = new COLLATIONKEY[5];
Keys[0] = Mycollator.getcollationkey (v1);
KEYS[1] = Mycollator.getcollationkey (v2);
Return (Keys[0].compareto (keys[1]));
}
--Non-comparison properties not compared
else if ("Java.lang.Boolean". Equals (Value1.getclass (). GetName ()) | | "Java.lang.Byte". Equals (Value1.getclass (). GetName ()))
{
return 0;
}else
{
BigDecimal B1 = new BigDecimal (value1.tostring ());
BigDecimal b2 = new BigDecimal (value2.tostring ());
Return B1.compareto (B2);
}

catch (Exception e)
{
System.out.println ("-----------------------------------------------------------------------------");
System.out.println ("---------object does not exist or does not allow reflection of this property at this security level, please refer to Java DOC--------");
System.out.println ("-----------------------------------------------------------------------------");
E.printstacktrace ();
}
Less than
return-1;
}
/**
* @param
* FieldName Property name
* Obj Object
* Reflection Gets the value of this property
* */
private static Object Getfieldvaluebyname (String fieldname,object obj)
{
Try
{
String letter = fieldname.substring (0,1). toUpperCase ();
String methodstr = "Get" +letter+fieldname.substring (1);
Method method = Obj.getclass (). GetMethod (Methodstr, New class[]{});

Object value = Method.invoke (obj, new object[]{});

return value;
}catch (Exception e)
{
System.out.println ("------------------------------------------------------");
System.out.println ("---------the" +fieldname+ "property does not exist----------------------");
System.out.println ("------------------------------------------------------");
return null;
}
}

}

//person

Package sort;

public class Person {
Public person () {}

private String name;
private int age;
Private long salary;

Public long getsalary () {
return salary;
}
public void Setsalary (long salary) {
This.salary = salary;
}
public int getage () {
return age;
}
public void Setage (int age) {
This.age = age;
}
Public String GetName () {
return name;
}
public void SetName (String name) {
THIS.name = name;
}

}