java字符串排序，小白求助

[SS帆]

import java.io.*;
import java.util.*;
import java.util.Comparator;

public class Main {
@SuppressWarnings("rawtypes")
public static void main(String[] args) throws Exception {
Scanner cin = new Scanner(System.in);
int n = cin.nextInt();
ArrayList songList = new ArrayList(n);
String str = cin.nextLine();
while (str != null) {
str = cin.nextLine();

if (str.length() == 1 || str.length() == 0)
continue;
songInfo a = new songInfo(str);
songList.add(a);
}

cin.close();
Collections.sort(songList, new sort());
System.out.println(songList);
}

}

class songInfo {
public String title;
public String composer;
public int runningTime;

public songInfo(String str) {
String[] song = str.split("&");
this.title = song[0];
this.composer = song[1];
this.runningTime = Integer.parseInt(song[2], 10);
;
}

public String getTitle() {
return title;
}

public String getComposer() {
return composer;
}

public int getRunningTime() {
return runningTime;
}

public String toString() {
return this.title + this.composer + this.runningTime;
}
}

class sort implements Comparator {

@Override
public int compare(Object o1, Object o2) {
songInfo s1 = (songInfo) o1;
songInfo s2 = (songInfo) o2;
if (s1.getRunningTime() < s2.getRunningTime())
return 1;
return -1;

}

}

输入样本：
3
&
Pink Frost&Phillipps, Martin&234933
Se quel guerrier io fossi&Puccini, Giacomo&297539
Non piu andrai&Mozart&234933
M'appari tutt'amor&Flotow, F&252905

输出：
Se quel guerrier io fossi&Puccini, Giacomo&297539
M'appari tutt'amor&Flotow, F&252905
Non piu andrai&Mozart&234933

输入第一行为输出的数量，第二行为分隔符，第三行开始是字符串由&分隔为三部分。
根据数字部分排序，遇到相同的根据第一部分字母排序。

自学java三个星期，写了几个小时就写出来上面那一片，现在没有头绪了。
能不能请帮忙改改？

[dislido]

import java.util.ArrayList;
import java.util.Scanner;
public class JTest {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        String sp = scanner.next();
        scanner.nextLine();
        while(scanner.hasNext()){
            list.add(scanner.nextLine());
        }
        scanner.close();
        
        list.sort((o1,o2)->{
            String []o1s = o1.split(sp);
            String []o2s = o2.split(sp);
            int o1i = Integer.valueOf(o1s[2]);
            int o2i = Integer.valueOf(o2s[2]);
            if(o1i == o2i)return o1s[0].compareTo(o2s[0]);
            return o2i-o1i;
        });
        
        for(int i = 0; i < num; i++){
            System.out.println(list.get(i));
        }
    }
}

[galiniur0u]

java8都可以这么写代码了，6666

[ImAmelie]

(o1,o2)->{...} 这是什么语法?

引用 1 楼 dislido 的回复:

import java.util.ArrayList;
import java.util.Scanner;
public class JTest {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        String sp = scanner.next();
        scanner.nextLine();
        while(scanner.hasNext()){
            list.add(scanner.nextLine());
        }
        scanner.close();
        
        list.sort((o1,o2)->{
            String []o1s = o1.split(sp);
            String []o2s = o2.split(sp);
            int o1i = Integer.valueOf(o1s[2]);
            int o2i = Integer.valueOf(o2s[2]);
            if(o1i == o2i)return o1s[0].compareTo(o2s[0]);
            return o2i-o1i;
        });
        
        for(int i = 0; i < num; i++){
            System.out.println(list.get(i));
        }
    }
}

[SS帆]

引用 1 楼 dislido 的回复:

import java.util.ArrayList;
import java.util.Scanner;
public class JTest {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        String sp = scanner.next();
        scanner.nextLine();
        while(scanner.hasNext()){
            list.add(scanner.nextLine());
        }
        scanner.close();
        
        list.sort((o1,o2)->{
            String []o1s = o1.split(sp);
            String []o2s = o2.split(sp);
            int o1i = Integer.valueOf(o1s[2]);
            int o2i = Integer.valueOf(o2s[2]);
            if(o1i == o2i)return o1s[0].compareTo(o2s[0]);
            return o2i-o1i;
        });
        
        for(int i = 0; i < num; i++){
            System.out.println(list.get(i));
        }
    }
}

原来可以这么精简

[dislido]

引用 3 楼 u013491662 的回复:

(o1,o2)->{...} 这是什么语法?

java 8 Lambda表达式，在这里会变成一个 Comparator