在java中，如果要对集合对象或数组对象进行排序，需要实现Comparator接口以达到我们想要的目标。
接下来我们模拟下在集合对象中对日期属性进行排序
一、实体类Step
?123456789101112131415161718192021222324252627282930313233343536373839404142 package com.ljq.entity; /** * 运号单流程 * * @author Administrator * */public class Step{ /** 处理时间 */ private String acceptTime = ""; /** 快件所在地点 */ private String acceptAddress = ""; public Step() { super(); } public Step(String acceptTime, String acceptAddress) { super(); this.acceptTime = acceptTime; this.acceptAddress = acceptAddress; } public String getAcceptTime() { return acceptTime; } public void setAcceptTime(String acceptTime) { this.acceptTime = acceptTime; } public String getAcceptAddress() { return acceptAddress; } public void setAcceptAddress(String acceptAddress) { this.acceptAddress = acceptAddress; } }
二、实现Comparator接口
?1234567891011121314151617181920212223242526272829 package com.ljq.entity; import java.util.Comparator; import java.util.Date; import com.ljq.util.UtilTool; /** * 对Step类进行排序 * * @author Administrator * */public class StepComparator implements Comparator<Step>{ /** * 如果o1小于o2,返回一个负数;如果o1大于o2，返回一个正数;如果他们相等，则返回0; */ @Override public int compare(Step o1, Step o2) { Date acceptTime1=UtilTool.strToDate(o1.getAcceptTime(), null); Date acceptTime2=UtilTool.strToDate(o2.getAcceptTime(), null); //对日期字段进行升序，如果欲降序可采用before方法 if(acceptTime1.after(acceptTime2)) return 1; return -1; } }
三、测试
?1234567891011121314151617181920212223242526 package junit; import java.util.Collection; import java.util.Collections; import java.util.List; import org.junit.Test; public class StepComparatorTest { @Test public void sort() throws Exception{ List<Step> steps=new ArrayList<Step>; //对集合对象进行排序 StepComparator comparator=new StepComparator(); Collections.sort(steps, comparator); if(steps!=null&&steps.size()>0){ for(Step step:steps){ System.out.println(step.getAcceptAddress()); System.out.println(step.getAcceptTime()); } } } }
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