本文實(shí)例講述了Java使用Comparable解決排序問題的方法。分享給大家供大家參考。具體實(shí)現(xiàn)方法如下:
一次舉重競(jìng)賽的比賽規(guī)則是:選手的成績(jī)以成功舉起的總重量來排序,舉起總重量多的排在前面;當(dāng)舉起總重量相同時(shí),按照體重來排序,體重輕的排在前面;要求程序讀取數(shù)據(jù)文件作為輸入,并按照上述規(guī)則排序后,打印出選手編號(hào);數(shù)據(jù)文件說明如下:現(xiàn)有5名選手,其選手編號(hào)、成功舉起的總重量及其體重如數(shù)據(jù)文件data4.txt,樣例內(nèi)容為:
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< p > < no >1</ no > < lw >140</ lw > < bw >54</ bw > </ p > < p > < no >2</ no > < lw >155</ lw > < bw >53</ bw > </ p > < p > < no >3</ no > < lw >140</ lw > < bw >42</ bw > </ p > < p > < no >4</ no > < lw >140</ lw > < bw >55</ bw > </ p > < p > < no >5</ no > < lw >130</ lw > < bw >46</ bw > </ p > |
首先我要解決的是文件解析的問題:
如何把文件內(nèi)容解析成想要的數(shù)據(jù):即提取出每個(gè)選手的編號(hào),成績(jī)和體重
我用一個(gè)實(shí)體Person來封裝這些屬性
整體代碼:
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import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.Arrays; public class forth { public static void main(String[] args) { ArrayList<Person> list= new ArrayList<Person>(); try { FileReader fr= new FileReader( "c:\\data.txt" ); BufferedReader br= new BufferedReader(fr); String str= null ; int num= 0 ; int score= 0 ; int weight= 0 ; int i= 0 ; while ((str=br.readLine())!= null ) { i++; if (i% 5 == 2 ) { str=str.trim().substring( 4 ,str.length()- 5 ); num=Integer.parseInt(str); str=br.readLine().trim(); str=str.substring( 4 ,str.length()- 5 ); score=Integer.parseInt(str); i++; str=br.readLine().trim(); str=str.substring( 4 ,str.length()- 5 ); weight=Integer.parseInt(str); i++; Person p= new Person(num,score,weight); list.add(p); } else continue ; } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } Person[] plist= new Person[list.size()]; list.toArray(plist); Arrays.sort(plist); for ( int i= 0 ;i<plist.length;i++) { System.out.print(plist[i].getNum()+ ". " +plist[i].getScore()+ " " +plist[i].getWeight()+ "\n\r" ); } } } class Person implements Comparable<Person>{ private int num; private int weight; private int score; public Person( int num, int score, int weight){ this .num=num; this .score=score; this .weight=weight; } @Override public int compareTo(Person other) { if ( this .score>other.score) return - 1 ; else if ( this .score<other.score) return 1 ; else return this .weight>other.weight? 1 :- 1 ; } public int getNum() { return num; } public void setNum( int num) { this .num = num; } public int getWeight() { return weight; } public void setWeight( int weight) { this .weight = weight; } public int getScore() { return score; } public void setScore( int score) { this .score = score; } } |
希望本文所述對(duì)大家的java程序設(shè)計(jì)有所幫助。