List排序的使用

1: list中包含的对象(TaskVO),实现接口Comparator

 

import java.io.Serializable;
import java.util.Comparator;

import com.comtop.product.scheme.planitem.PlanItemConstants;
import com.comtop.product.scheme.planitem.util.PlanItemUtil;

 

public class TaskVO implements Serializable,Comparator {

    /** 地点名称 */
    private String placeName;

    /** 工作内容 */
    private String workContent;

    /** 电压等级 */
    private int voltageLevel;

 

    public String getPlaceName() {
        return placeName;
    }

    public void setPlaceName(String placeName) {
        this.placeName = placeName;
    }

    public int getVoltageLevel() {
        return voltageLevel;
    }

    public void setVoltageLevel(int voltageLevel) {
        this.voltageLevel = voltageLevel;
    }

    public String getWorkContent() {
        return workContent;
    }

    public void setWorkContent(String workContent) {
        this.workContent = workContent;
    }

    

    // 实现排序接口需要的方法(单个属性排序)

    public int compare(Object arg0, Object arg1) {
       TaskVO taskVO1 = (TaskVO)arg0;
       TaskVO taskVO2 = (TaskVO)arg1;
       // 如果需要升序排列
        return String.valueOf(taskVO1.getVoltageLevel()).compareTo(String.valueOf(taskVO2.getVoltageLevel()));
       // 如果需要降序排列
        return String.valueOf(taskVO2.getVoltageLevel()).compareTo(String.valueOf(taskVO1.getVoltageLevel()));
   }

 

// 如果需要实现多个属性排序则需要将上面的方法改成如下

public int compare(Object arg0, Object arg1) {
       TaskVO taskVO1 = (TaskVO)arg0;
       TaskVO taskVO2 = (TaskVO)arg1;
        int flag = String.valueOf(taskVO1.getVoltageLevel()).compareTo(String.valueOf(taskVO2.getVoltageLevel()));
       if(flag == 0){
           return taskVO1.getPlaceName().compareTo(taskVO2.getPlaceName());
       }else{
           return flag;
       }
   }
}

2:在需要排序的地方进行调用以下实现即可(假设tasks是一个list对象,里面包含若干个taskVO)

   TaskVO taskVO = new TaskVO();
   Collections.sort(tasks,taskVO);

后面得到的tasks就是排序过的list