在java中將3個數組打印為表格

Question

在java中將3個數組打印為表格

我嘗試以不同的方式將 3 個數組打印為表格。 但我想知道以正確的方式做。 請幫我。

這 3 個是我的數組

Object[] arrayObjects = new GetDataFromDB().projectDB();
String[] arr_projectID = (String[])arrayObjects[0];
String[] arr_projectName = (String[])arrayObjects[1];
int[] arr_projectStatus = (int[])arrayObjects[2];

我怎樣才能像這樣打印表格，

     -------- Project Table --------
| ProjectID | ProjectName | ProjectStatus |
|     01    |     p001    |       20      |
|     02    |     p002    |       70      |
|     03    |     p003    |       45      |
|     ..    |     ....    |       ..      |
|     ..    |     ....    |       ..      |

我是這樣試的

        String printPID ="";
        String printPName ="";
        String printPStatus ="";
        
        for (int i = 0; i < arr_projectID.length; i++) {
            
             pID = pID +"\n" + arr_projectID[i];
             printPID = "Project ID" + pID + "\n";
        } 
        
         for (int i = 0; i < arr_projectName.length; i++) {
            
             pName = pName + "\n" + arr_projectName[i];
             printPName = "Project name" + pName + "\n";
        } 
         
          for (int i = 0; i < arr_projectStatus.length; i++) {
            
             pStatus = pStatus + "\n" + arr_projectStatus[i];
             printPStatus = "Project Status" + pStatus + "\n";
        }

Answer 1

您應該將三個單獨的數組組合成一個二維String數組。 這使相似的元素保持在一起。

使用二維String數組，我創建了這個輸出。 我使用更長的項目名稱來說明如何計算列寬以創建表格。

              -------- Project Table --------               
| Project ID |        Project Name         | Project Status | 
|     01     |       Create Project        |       20       | 
|     02     |   Create PrintTable class   |       70       | 
|     03     |    Test PrintTable class    |       45       | 
|     04     | Write Stack Overflow Answer |       30       | 

當您面對復雜的應用程序時，您可以將任務划分為更小的任務。 您一直在划分，直到您可以對每個任務進行編碼。 創建任務列表的一種方法是編寫偽代碼。

我用來創建這個輸出的偽代碼是這樣的：

Define table name
Define field names
Initialize a 2D String array of projects
Create the output table
    Calculate the maximum size of each column
    Calculate the total width of the table
    Create the table header
    Create the header line
        Center each field title
    For each project
        Create a detail line
            Center each value
Print the output table.

我廣泛使用StringBuilder類來創建輸出表。

我還使用方法重載來創建兩個基本上做同樣事情的方法。 居中一些文本。 有兩種方法的原因是，在一個實例中，我輸入了一個StringBuilder 。 在第二個實例中，我輸入了一個String 。

這是完整的可運行示例。

public class PrintTable {

    public static void main(String[] args) {
        String tableName = "Project";
        String[] fieldNames = new String[] { "ID", "Name", "Status" };
        
        PrintTable printTable = new PrintTable();
        System.out.println(printTable.createTable(tableName, fieldNames));
    }
    
    private String[][] results;
    
    public PrintTable() {
        String[][] results = { { "01", "Create Project", "20" },
                { "02", "Create PrintTable class", "70" },
                { "03", "Test PrintTable class", "45" },
                { "04", "Write Stack Overflow Answer", "30" }
        };
        this.results = results;
    }
    
    public String createTable(String tableName, String[] fieldNames) {
        int[] maxWidth = calculateMaximumColumnWidth(tableName, fieldNames);
        int totalWidth = calculateTotalLineWidth(fieldNames, maxWidth);
        
        StringBuilder builder = createTable(tableName, fieldNames, 
                maxWidth, totalWidth);
        return builder.toString();
    }

    private int[] calculateMaximumColumnWidth(String tableName, 
            String[] fieldNames) {
        int[] maxWidth = new int[fieldNames.length];
        
        for (int i = 0; i < fieldNames.length; i++) {
            maxWidth[i] = tableName.length() + fieldNames[i].length() + 1;
        }
        
        for (int row = 0; row < results.length; row++) {
            for (int column = 0; column < results[row].length; column++) {
                maxWidth[column] = Math.max(maxWidth[column], 
                        results[row][column].length());
            }
        }
        
        return maxWidth;
    }

    private int calculateTotalLineWidth(String[] fieldNames, int[] maxWidth) {
        int totalWidth = fieldNames.length;
        for (int i = 0; i < fieldNames.length; i++) {
            totalWidth += maxWidth[i] + 2;
        }
        return totalWidth;
    }

    private StringBuilder createTable(String tableName, String[] fieldNames, 
            int[] maxWidth, int totalWidth) {
        StringBuilder builder = new StringBuilder();
        builder.append(createTitleLine(tableName, totalWidth));
        builder.append(System.lineSeparator());
        builder.append(createHeaderLine(tableName, fieldNames, maxWidth));
        builder.append(System.lineSeparator());
        builder.append(createDetailLines(maxWidth));
        return builder;
    }
    
    private StringBuilder createTitleLine(String tableName, int length) {
        StringBuilder builder = new StringBuilder();
        builder.append(createLine('-', 8));
        builder.append(" ");
        builder.append(tableName);
        builder.append(" Table ");
        builder.append(createLine('-', 8));
        return centerText(builder, length);
    }
    
    private StringBuilder createHeaderLine(String tableName, 
            String[] fieldNames, int[] maxWidth) {
        StringBuilder builder = new StringBuilder();
        builder.append("| ");
        for (int i = 0; i < fieldNames.length; i++) {
            StringBuilder text = new StringBuilder();
            text.append(tableName);
            text.append(" ");
            text.append(fieldNames[i]);
            builder.append(centerText(text, maxWidth[i]));
            builder.append(" | ");
        }
        return builder;
    }
    
    private StringBuilder createDetailLines(int[] maxWidth) {
        StringBuilder builder = new StringBuilder();
        
        for (int row = 0; row < results.length; row++) {
            builder.append("| ");
            for (int column = 0; column < results[row].length; column++) {
                builder.append(centerText(results[row][column], maxWidth[column]));
                builder.append(" | ");
            }
            builder.append(System.lineSeparator());
        }
        
        return builder;
    }
    
    private StringBuilder centerText(String text, int length) {
        StringBuilder builder = new StringBuilder(length);
        builder.append(text);
        return centerText(builder, length);
    }
    
    private StringBuilder centerText(StringBuilder text, int length) {
        if (text.length() >= length) {
            return text;
        }
        
        int spaces = (length - text.length()) / 2;
        text.insert(0, createLine(' ', spaces));
        return text.append(createLine(' ', length - text.length()));
    }
    
    private StringBuilder createLine(char c, int length) {
        StringBuilder builder = new StringBuilder(length);
        
        for (int i = 0; i < length; i++) {
            builder.append(c);
        }
        
        return builder;
    }

}

Answer 2

public class Foo {

    public static void main(String... args) throws IOException, InterruptedException {
        String[] ids = { "01", "02", "03" };
        String[] names = { "p001", "p002", "p003" };
        int[] statuses = { 20, 70, 45 };

        printTable(ids, names, statuses);
    }

    private static final String ID_COLUMN_NAME = "ProjectID";
    private static final String NAME_COLUMN_NAME = "ProjectName";
    private static final String STATUS_COLUMN_NAME = "ProjectStatus";

    public static void printTable(String[] ids, String[] names, int[] statuses) {
        int idColumnWidth = Math.max(ID_COLUMN_NAME.length() + 2, getMaxLength(ids));
        int nameColumnWidth = Math.max(NAME_COLUMN_NAME.length() + 2, getMaxLength(names));
        int statusColumnWidth = Math.max(STATUS_COLUMN_NAME.length() + 2, getMaxLength(statuses));
        int tableWidth = idColumnWidth + nameColumnWidth + statusColumnWidth + 4;

        System.out.println(middle("-------- Project Table --------", tableWidth));
        System.out.println('|' + middle(ID_COLUMN_NAME, idColumnWidth) +
                '|' + middle(NAME_COLUMN_NAME, nameColumnWidth) +
                '|' + middle(STATUS_COLUMN_NAME, statusColumnWidth) + '|');

        for (int i = 0; i < ids.length; i++)
            System.out.println('|' + middle(ids[i], idColumnWidth) +
                    '|' + middle(names[i], nameColumnWidth) +
                    '|' + middle(String.valueOf(statuses[i]), statusColumnWidth) + '|');
    }

    private static int getMaxLength(String[] arr) {
        return Arrays.stream(arr)
                     .mapToInt(String::length)
                     .max().orElse(0);
    }

    private static int getMaxLength(int[] arr) {
        return Arrays.stream(arr)
                     .mapToObj(String::valueOf)
                     .mapToInt(String::length)
                     .max().orElse(0);
    }

    private static String middle(String str, int columnWidth) {
        StringBuilder buf = new StringBuilder(columnWidth);
        int offs = (columnWidth - str.length()) / 2;

        for (int i = 0; i < offs; i++)
            buf.append(' ');

        buf.append(str);

        while (buf.length() < columnWidth)
            buf.append(' ');

        return buf.toString();
    }

}

輸出：

      -------- Project Table --------      
| ProjectID | ProjectName | ProjectStatus |
|    01     |    p001     |      20       |
|    02     |    p002     |      70       |
|    03     |    p003     |      45       |

Answer 3

桌子幾乎和你的照片一樣，哈哈

package com.company;

import java.util.ArrayList;
import java.util.List;

public class Main {

    private String itemName;
    private double price;
    private int quantity;


    public Main(String itemName, double price, int quantity) {
        this.setItemName(itemName);
        this.setPrice(price);
        this.setQuantity(quantity);
    }


    public String getItemName() {
        return itemName;
    }

    public void setItemName(String itemName) {
        this.itemName = itemName;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getQuantity() {
        return quantity;
    }

    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }


    public static void printInvoiceHeader() {
        System.out.println(String.format("%30s %25s %10s %25s %10s", "Project ID", "|", "Project Name", "|", "Project Status"));
        System.out.println(String.format("%s", "----------------------------------------------------------------------------------------------------------------"));
    }

    public void printInvoice() {
        System.out.println(String.format("%30s %25s %10.2f %25s %10s", this.getItemName(), "| p", this.getPrice(), "|", this.getQuantity()));
    }

    public static List<Main> buildInvoice() {
        List<Main> itemList = new ArrayList<>();
        itemList.add(new Main("01", 1, 20));
        itemList.add(new Main("02", 2, 70));
        itemList.add(new Main("03", 3, 45));
        return itemList;
    }

    public static void main(String[] args) {

        Main.printInvoiceHeader();
        Main.buildInvoice().forEach(Main::printInvoice);
    }
}