使用Java对汽车列表进行排序并显示它们排序？答案

【问题标题】：Sort the list of cars and display them sort by make using Java?使用Java对汽车列表进行排序并显示它们排序？
【发布时间】：2021-07-23 18:12:02
【问题描述】：

我有一个问题，要对 txt 文件的汽车报告中的数据进行排序。

问题是：我如何列出按 MAKE（福特、雪佛兰等）分类的汽车。它们只需要对 MAKE 进行排序，这样它们就可以是彼此之下的所有福特汽车，然后是雪佛兰、道奇 .. 等等，像这样：

这就是我目前所拥有的：

这是我的源代码：


public class CustomerSale {

    // Details of reports
    private String zipCodeExtension;

    private int customerNumber;

    private String customerName;

    private int purchaseDate;

    private String make;

    private int purchasePrice;

    private int yearOfVehicle;

    private int satisfactionRating;



    // Create constructor argument

    public CustomerSale(String zipCodeExtension, int customerNumber, String customerName,
                        int purchaseDate, String make, int purchasePrice,
                        int yearOfVehicle, int satisfactionRating) {
        this.zipCodeExtension = zipCodeExtension;
        this.customerNumber = customerNumber;
        this.customerName = customerName;
        this.purchaseDate = purchaseDate;
        this.make = make;
        this.purchasePrice = purchasePrice;
        this.yearOfVehicle = yearOfVehicle;
        this.satisfactionRating = satisfactionRating;
    }


    // Create getters and setters

    public String getMake() {

        return make;

    }

    public void setMake(String make) {

        this.make = make;

    }


    public String getZipCodeExtension() {

        return zipCodeExtension;

    }

    public void setZipCodeExtension(String zipCodeExtension) {

        this.zipCodeExtension = zipCodeExtension;

    }

    public int getCustomerNumber() {

        return customerNumber;

    }

    public void setCustomerNumber(int customerNumber) {

        this.customerNumber = customerNumber;

    }

    public String getCustomerName() {

        return customerName;

    }

    public void setCustomerName(String customerName) {

        this.customerName = customerName;

    }

    public int getPurchaseDate() {

        return purchaseDate;

    }

    public void setPurchaseDate(int purchaseDate) {

        this.purchaseDate = purchaseDate;

    }

    public double getPurchasePrice() {

        return purchasePrice;

    }

    public void setPurchasePrice(int purchasePrice) {

        this.purchasePrice = purchasePrice;

    }

    public int getYearOfVehicle() {

        return yearOfVehicle;

    }

    public void setYearOfVehicle(int yearOfVehicle) {

        this.yearOfVehicle = yearOfVehicle;

    }


    public int getSatisfactionRating() {

        return satisfactionRating;

    }

    public void setSatisfactionRating(int satisfactionRating) {

        this.satisfactionRating = satisfactionRating;

    }
}


import java.io.*;
import java.text.DecimalFormat;
import java.util.*;

public class SortByMake {
    public static void main(String[] args) throws FileNotFoundException {

        File carsInfo = new File("src/custsale.txt");
        Scanner carsScanner = new Scanner(carsInfo);
        String format = "%-20s%-14s%-21s%-16s%-19s$%-17s%-14s%-20s\n";

        while (carsScanner.hasNextLine()) {
            // Read the carsScanner
            String zipCodeExtension = carsScanner.nextLine();
            int customerNumber = Integer.parseInt(carsScanner.nextLine());
            String customerName = carsScanner.nextLine();
            int purchaseDate = Integer.parseInt(carsScanner.nextLine());
            String make = carsScanner.nextLine();
            int purchasePrice = Integer.parseInt(carsScanner.nextLine());
            int yearOfVehicle = Integer.parseInt(carsScanner.nextLine());
            int satisfactionRating = Integer.parseInt(carsScanner.nextLine());
            CustomerSale custsale = new CustomerSale(zipCodeExtension, customerNumber, customerName,
                    purchaseDate, make, purchasePrice, yearOfVehicle, satisfactionRating);

                // Display the report
                DecimalFormat df = new DecimalFormat("#,#####");
                System.out.printf(format, custsale.getZipCodeExtension(), custsale.getCustomerNumber(),
                        custsale.getCustomerName(), custsale.getPurchaseDate(), custsale.getMake(),
                        df.format(custsale.getPurchasePrice()), custsale.getYearOfVehicle(),
                        custsale.getSatisfactionRating());
        }

        ArrayList<CustomerSale> carMake = new ArrayList<>();

        Collections.sort(carMake, Comparator.comparing(CustomerSale::getMake));


        final int pageSize = 30;
        int carCounter = 0;
        for(CustomerSale car : carMake){

            if (carCounter % pageSize == 0) {
                printPageHeader(carCounter / pageSize + 1);
            }

            // Increment the car counter
            carCounter++;

        }

        carsScanner.close();

    }

    private static void printPageHeader(int i) {
        System.out.println(
                "-------------------------------------------------ABC USED CARS----------------------------------------------------------------");
        System.out.println(
                "-------------------------------------------------------" + "PAGE " + i + "-----------------------------------------------------------------");
        System.out.printf("%-19s%-15s%-21s%-15s%-20s%-17s%-12s%-20s\n", "|ZIP CODE-EXT|", "|CUST No.|", "|CUSTOMER NAME|", "|DoP|",
                "|MAKE|", "|PRICE|", "|YEAR|", "|RATE|");
        System.out.println(
                "------------------------------------------------------------------------------------------------------------------------------");
    }

}

这里是文本文件报告：

46410-1234
1001
ALBERT, CARL T.
08252001
FORD
0255000
1991
2
46307-1201
1003
ANDREWS, ROBERT
08262001
CHEVROLET
0700000
1958
0
46423-2311
1008
ANZIO, RAFELINO
09012001
CHEVROLET
0456050
1978
0
46424-0121
1010
ASHLEY, WILLIAM B.
09022001
PIERCE-ARROW
1240000
1932
2
46375-3110
1015
ATKINSON, MARK
08272001
STUDEBAKER
0050000
1958
1
46405-1291
1025
AVERY, ALFRED A.
08292001
HUDSON
0230000
1954
1
46301-1234
1031
BEZZMEK, JENNIFER
08272001
FORD
0455000
1995
2
46303-1201
1033
BLAKE, DONALD
08292001
FORD
0722050
1989
1
46413-2311
1041
BLONDELL, BONNIE
09042001
CHEVROLET
0356050
1988
1
46404-0121
1045
BONADIO, JAMES
09032001
PIERCE-ARROW
1150000
1935
2
46307-3110
1055
BUCKO, ONIEDA
08282001
STUDEBAKER
0245000
1964
1
46410-1291
1056
BYMANN, FREDRICK
08292001
FORD
0330000
1994
1
46342-1234
1061
CALBERT, RONALD
09052001
FORD
0355000
1993
2
46307-1211
1063
CHELSEA, MARTHA S.
08302001
DODGE BROS.
0350000
1935
0
46410-2311
1067
CLAFLIN, WAYNE R.
09012001
CHEVROLET
0456050
1990
2
46410-0121
1070
COLE, CHARLES C.
09022001
PIERCE-ARROW
1050000
1929
2
46305-3111
1075
COLEMAN, THOMAS
08272001
STUDEBAKER
0167050
1961
1
46410-1221
1076
COLWELL, RICHARD L.
08292001
HUDSON
0430000
1940
1
46414-1231
1080
COOPER, JOHNATHAN
09052001
FORD
1256000
1996
2
46307-1201
2002
COREY, SARAH D.
08272001
CHEVROLET
0650050
1994
0
46421-2311
2004
CRACKLIN, GOODMAN
09012001
CHEVROLET
1456050
1996
0
46323-0121
2011
CRAWFORD, TIMOTHY
09012001
PIERCE-ARROW
1040000
1931
2
46315-3110
2012
CURRIE, RAYMOND
08282001
STUDEBAKER
0150025
1956
1
46425-1291
2024
CYBORG, IZORE M.
09052001
HUDSON
0130000
1949
1
46410-1234
2031
DALTON, DAVID P.
08252001
FORD
0234000
1990
2
46307-1201
2043
DAVIES, RALPH O.
08262001
CHEVROLET
0333000
1989
0
46423-2311
2048
DENNICK, DONNA
09012001
CHEVROLET
0656025
1995
0
46424-0121
2050
DERBIN, DEANNA
09022001
PIERCE-ARROW
1640025
1937
2
46375-3110
2065
DONNEHUE, PHILLIP
09042001
STUDEBAKER
0054000
1966
1
46405-1291
2085
DOPPLER, RADAR O.
08302001
HUDSON
0311000
1951
1
46310-1234
2091
DUNLOP, RITA
08252001
FORD
1450045
1996
2
46303-1201
3003
DYKES, CYNTHIA
08262001
FORD
0410050
1987
1
46413-2311
3011
EATON, ESTER B.
09012001
CHEVROLET
1356050
1996
0
46404-0121
3015
EFFLEY, BAILY
09022001
PIERCE-ARROW
1446045
1933
2
46307-3110
3025
EGGERTON, AMANDA
08292001
STUDEBAKER
0335000
1965
1
46410-1291
3026
EPPLEY, DAVID
08282001
FORD
0414000
1995
1
46342-1234
3031
ERKLE, ROSA
09032001
FORD
0355020
1993
2
46307-1211
3043
FARNSWORTH, WESLEY
09052001
DODGE BROS.
1150000
1996
0
46410-2311
3047
FLANNERY, JAMES
09012001
CHEVROLET
0450050
1992
0
46410-0121
3050
FOREMAN, OTTO J.
09022001
PIERCE-ARROW
0940000
1927
2
46305-3111
3055
FOWLER, KATHLEEN
08272001
STUDEBAKER
0267050
1964
1
46410-1221
3056
FURNACE, DAVID
08292001
HUDSON
0530000
1948
1
46414-1231
3061
GALLAGHER, CLARENCE
0904200
1FORD
1006000
1992
2
46307-1201
3062
GENNERRO, TONY S.
08302001
CHEVROLET
0320050
1989
0
46421-2311
3066
GOEBEL, NANCY K.
09022001
CHEVROLET
0643050
1990
0
46323-0121
3072
GUNTHER, FREDERICK
09032001
PIERCE-ARROW
1260000
1930
2
46315-3110
3080
HAINES, MARSHALL
08292001
STUDEBAKER
02500251
959
1
46425-1291
3094
HANCOCK, JONATHON
09032001
HUDSON
0330000
1953
1
46423-2311
3098
HARTNETT, ROBERTO
09052001
CHEVROLET
0326040
1988
0
46424-0121
4005
HENNING, SONIA
09052001
PIERCE-ARROW
1305000
1928
2
46375-3110
4009
HORNSBY, ROGERS
08252001
STUDEBAKER
0167500
1962
1
46405-1291
4012
HYATT, JANET F.
08302001
HUDSON
0155000
1951
1
46301-1234
4021
IDZIOR, RAYMOND
09012001
FORD
1460000
1996
2
46303-1201
4022
JENNINGS, WILLIAM
08262001
FORD
0612040
1992
1
46410-2311
4024
JOHNSON, JACK
09032001
CHEVROLET
0256050
1985
0
46404-0121
4032
KULKA, ROBERT C.
09042001
PIERCE-ARROW
0970000
1934
2
46307-3110
4035
KURTZ, DONALD
08302001
STUDEBAKER
0345000
1966
1
46410-1291
4038
LEVANDOWSKI, JILL
08282001
DODGE BROS.
0430000
1988
1
46342-1234
4044
METZ, ARNOLD E.
09012001
FORD
1323000
1996
2
46307-1211
4046
NORRIS, CHARLES S.
09052001
CHEVROLET
0844000
1992
0
46410-2311
4047
NOWAKOWSKI, ALFRED
09012001
DODGE BROS.
0656050
1994
1
46410-0121
4053
O'BOYLE, NIEL
09032001
PIERCE-ARROW
1550000
1938
2
46305-3111
4056
O'BRIAN, PATRICK
08302001
STUDEBAKER
0347050
1962
1
46410-1221
4059
PATTERSON, LENNI R.
08292001
HUDSON
0250000
1946
1
46414-1231
4061
PERRY, SHAMUS
09052001
FORD
0895000
1994
2
46307-1201
4066
REED, ROBERT B.
08272001
CHEVROLET
0740050
1996
0
46421-2311
4067
RODRIGUEZ, ALONZO
09052001
DODGE BROS.
1050050
1995
0
46323-0121
4073
SANCHEZ, HENRY
09012001
PIERCE-ARROW
0830000
1925
2
46315-3110
4081
SWARTZ, HECTOR
08282001
STUDEBAKER
0075025
1954
1
46301-1234
4084
TORREZ, MARTIN
0827200
1FORD
0565000
1994
2
46303-1201
4090
TUTTLE, MARK
08292001
FORD
0710050
1996
1
46413-2311
4094
WARNER, JACK
09042001
CHEVROLET
0856050
1996
0
46404-0121
4115
YACKLEY, YOURTO
09042001
PIERCE-ARROW
1000000
1930
2

【问题讨论】：

您正在打印从文件中读取的数据。您需要将其存储在可以排序然后打印的数据结构（如List）中。
我在你的代码中没有看到任何可以对汽车进行分类的东西
@JohnnyMopp 正确，这就是我在我的代码中尝试做的事情（更新），但我需要有人来纠正我的代码，所以我看到的就像第一张图片一样。
@Berto99 我的错，我刚刚注意到了，我更新了我的代码。

标签： java file sorting bufferedreader txt

【解决方案1】：

这很简单：

读取所有元素并将它们放入列表中：

ArrayList<CustomerSale> sales = new ArrayList<>();
while(...){
    sales.add(custsale);
}

对元素进行排序（我正在使用流，但可能Collections.sort 可能会更便宜，因为它是就地的，例如Comparator.comparing(CustomerSale::getMake)，谢谢@Thomas）：
```
List<CustomerSale> sorted = sales.stream().sorted((f,s) -> {
    return f.getMake().compareTo(s.getMake());
}).collect(Collectors.toList());
```

仅在最后，打印输出：

for(int i = 0; i < sorted.size(); i++){
    CustomerSale custsale = sorted.get(i);
    if (i % pageSize == 0) {
        printPageHeader(i / pageSize + 1);
    }

    DecimalFormat df = new DecimalFormat("#,#####");
    System.out.printf(format, custsale.getZipCodeExtension(), custsale.getCustomerNumber(),
            custsale.getCustomerName(), custsale.getPurchaseDate(), custsale.getMake(),
            df.format(custsale.getPurchasePrice()), custsale.getYearOfVehicle(),
            custsale.getSatisfactionRating());
};

【讨论】：

请注意，比较器可以通过Comparator.comparing(CustomerSale::getMake) 创建，这样更易于阅读。添加另一个级别就像Comparator.comparing(CustomerSale::getMake).thenComparingInt(CustomerSale::getPurchaseDate) 或Comparator.comparing(CustomerSale::getMake).thenComparing(CustomerSale::getZipCodeExtension)。
@Berto99 太好了，您的代码已经完成了工作，但是为什么页面 # 没有更新。我认为这条线改变了一些东西：if (i % pageSize == 0) { printPageHeader(carCounter / pageSize + 1); }
@MoFatah 这是一个错字。您根本不需要carCounter，打印标题的调用现在应该是printPageHeader(i/ pageSize + 1);。由于页码取决于已打印的元素数量，因此您需要使用代表该元素的内容 - 在该循环的情况下，该索引将是索引 i。
@Thomas 太棒了，我修好了。谢谢托马斯，谢谢 Berto99。你们是传奇。