java实现集合对象排序(多个字段)

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实现了集合的多列升序降序排列，可以支持中文字符,null字段

package com.test;
import java.lang.reflect.Method;  
import java.text.Collator;
import java.util.ArrayList;  
import java.util.Collections;  
import java.util.Comparator;  
import java.util.List;  
  
public class MutilOrder implements Comparator<Object> {  
    String[] fields = null;  
    String[] orders=null;
    boolean isValue;  
    Collator cmp = Collator.getInstance(java.util.Locale.CHINA);
    
    public MutilOrder() {
		super();
	}
	public MutilOrder(String[] fields, String[] orders) {
		super();
		this.fields = fields;
		this.orders = orders;
	}
	public String[] getFields_user() {  
        return fields;  
    }  
    public void setFields(String[] fields_user) {  
        this.fields = fields_user;  
    }  
 
    public String[] getOrders() {
		return orders;
	}
	public void setOrders(String[] orders) {
		this.orders = orders;
	}
	public int compare(Object obj1, Object obj2) { 
        // 没有属性，则不排序  
        if (fields == null || fields.length <= 0) {  
            return 2;// 不比较  
        }  
        for (int i = 0; i < fields.length;i++ ) {  
        	int ret=compareField(obj1, obj2, fields[i]);
        	if (ret==0) {
				continue;
			}
            if (ret!=0) {
            	if ("asc".equalsIgnoreCase(orders[i])) {
            		return ret;
				}else if("desc".equalsIgnoreCase(orders[i])) {
					return ret*-1;
				}
			}else {
				continue;
			}
        }  
        return 0;  
    }  

    private int compareField(Object o1, Object o2, String fieldName) {  
        Object value1=getFieldValueByName(fieldName, o1);  
        Object value2=getFieldValueByName(fieldName, o2); 
        if (value1==null ||value2==null) {
			if (value1!=null) {
				return 1;
			}if (value2!=null) {
				return -1;
			}else {
				return 0;
			}
		} 
        if (isValue) {  
            double v1 = ((Number)value1).doubleValue();  
            double v2 = ((Number)value2).doubleValue();  
            if (v1-v2 > 0) {  
                return 1;  
            }else if (v1==v2) {
				return 0;
			}
            return -1;  
        } else {  
            String v1 = value1.toString();  
            String v2 = value2.toString();  
            int i= cmp.compare(v1, v2);
            if (i>0) {
				return 1;
			}else if (i==0) {
				return 0;
			}
            return -1;  
        }  
    }  
    private Object getFieldValueByName(String fieldName, Object obj) {  
        try {  
            Class<? extends Object> objClass = obj.getClass();  
            String Letter = fieldName.substring(0, 1).toUpperCase();  
            String methodStr = "get" + Letter + fieldName.substring(1);  
  
            Method method = objClass.getMethod(methodStr, new Class[] {});  
            Object value = method.invoke(obj, new Object[] {});  
  
            if (value instanceof Number) {  
                this.setValue(true);  
            } else {
            	 this.setValue(false); 
			}
  
            return value;  
        } catch (Exception e) {  
            System.err.println("FieldName:" + fieldName + " is not exsited.");  
            return null;  
        }  
    }  
  
    public boolean isValue() {  
        return isValue;  
    }  
  
    public void setValue(boolean isValue) {  
        this.isValue = isValue;  
    }  

    public static void main(String[] args) {  
        List<JavaBean> list = new ArrayList<JavaBean>();  
        JavaBean bean = new JavaBean(4,"张三0.01","a");  
        list.add(bean);  
        bean = new JavaBean(3,"张三0.001","a");  
        list.add(bean);  
        bean = new JavaBean(2,"王五","b");  
        list.add(bean);  
        bean = new JavaBean(1,"钱七","b");  
        list.add(bean);  
        MutilOrder comparator = new MutilOrder();  
        comparator.setFields(new String[] {"address","name","id"}); 
        comparator.setOrders(new String[] {"asc","desc","asc"});
        Collections.sort(list, comparator);  
        for (JavaBean obj : list) {  
            System.out.println(obj.getId()+":"+obj.getName()+":"+obj.getAddress());  
        }  
        System.out.println("OK");
    }  
}  
class JavaBean{  
    private String name;  
    private String address;  
    private int id;  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
    public String getAddress() {  
        return address;  
    }  
    public void setAddress(String address) {  
        this.address = address;  
    }  
    public int getId() {  
        return id;  
    }  
    public void setId(int id) {  
        this.id = id;  
    }  
    public JavaBean(int id,String name, String address) {  
        super();  
        this.name = name;  
        this.address = address;  
        this.id = id;  
    }  
}  

结果

4:张三0.01:a
3:张三0.001:a
2:王五:b
1:钱七:b
OK