我有一个看起来像这样的大csv文件
Order ID,Order Priority,Order Quantity,Unit Price,Ship Mode,Customer Name,Customer Segment,Product Category
3,Low,6,38.94,Regular Air,Muhammed MacIntyre,Small Business,Office Supplies
293,High,49,208.16,Delivery Truck,Barry French,Consumer,Office Supplies
293,High,27,8.69,Regular Air,Barry French,Consumer,Office Supplies
483,High,30,195.99,Regular Air,Clay Rozendal,Corporate,Technology
我可以显示它，但我不知道如何对它进行排序并再次显示它排序。到目前为止，这是我的代码
package project1;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;
public class Test {
public static void main(String[] args) throws FileNotFoundException {
Scanner input = new Scanner(System.in);
int choice=0;
boolean flag = true;
while (flag) {
System.out.println("Enter 1 to display data.");
System.out.println("Enter 2 to sort data.");
System.out.println("Enter 3 to idk.");
System.out.println("Enter 0 to exit.");
System.out.print("Your choice: ");
choice = input.nextInt();
if (choice ==1) {
File inputFile = new File("dataToLoad.csv");
String line;
String delimiter = ",";
Scanner in = new Scanner(inputFile);
int numberOfLines = 0;
int numberOfColumns = 0;
while (in.hasNextLine()){
line = in.nextLine();
numberOfLines++;
}
in.close();
String[][] data = new String[numberOfLines][8];
in = new Scanner(inputFile);
int currentRow = 0;
while (in.hasNextLine()){
line = in.nextLine();
String[] parts = line.split(delimiter);
numberOfColumns = parts.length;
for (int i = 0; i<numberOfColumns; i++) {
data[currentRow][i] = parts[i];
}
currentRow++;
}
in.close();
System.out.println(Arrays.deepToString(data));
for (int row=0; row<numberOfLines; row++) {
for (int col=0; col<numberOfColumns; col++) {
System.out.printf("%-20s", data[row][col]);
}
System.out.println();
}
}
else {
if (choice ==2) {
}
else
if (choice==0) {
System.out.println("Good bye!");
flag = false;
}
else System.out.println("I am sorry, this is not a valid option. Please try again.");
}
}
}
}
正如您所看到的，我为用户提供了显示数据的选项，显示它们的排序（根据id），我还希望用户选择如何对代码进行排序。我被困在排序。
答案 0 :(得分：2)
RowClass。String[] RowClass的一个实例。RowClass个对象存储在List;我将此称为rowList。rowList对Comparator进行排序。为每个排序选项创建一个Comparator。RowClass.toString()以显示一行。答案 1 :(得分：0)
这应该有所帮助，我相信你会弄清楚这里发生了什么
<强> Main.java
package pkg;
import java.util.Arrays;
import static pkg.Order.OrderBuilder;
public class Main {
private static Order[] orders = new Order[3];
private static OrderBuilder orderBuilder = new OrderBuilder();
public static void main(String[] args) {
Order order1 = orderBuilder.createNewOrder().withId(10).withCustomerName("John").withPrice(1.23f).withPriority("high").build();
Order order2 = orderBuilder.createNewOrder().withId(20).withCustomerName("Lee").withQuantity(3.4f).build();
Order order3 = orderBuilder.createNewOrder().withId(30).withCustomerName("Someone").withPriority("low").build();
orders[0] = order3;
orders[1] = order1;
orders[2] = order2;
System.out.println("Before sorting");
for(int i = 0; i < orders.length; i++) {
System.out.println(orders[i].getId());
}
Arrays.sort(orders);
System.out.println("After sorting");
for(int i = 0; i < orders.length; i++) {
System.out.println(orders[i].getId());
}
}
}
<强> Order.java
package pkg;
public class Order implements Comparable<Order> {
private int id;
private String priority;
private float quantity;
private float price;
private String shipMode;
private String customerName;
private String customerSegment;
private String productCategory;
private void setId(int id) {
this.id = id;
}
int getId() {
return this.id;
}
private void setPriority(String priority) {
this.priority = priority;
}
private void setQuantity(float quantity) {
this.quantity = quantity;
}
private void setPrice(float price) {
this.price = price;
}
private void setShipMode(String shipMode) {
this.shipMode = shipMode;
}
private void setCustomerName(String customerName) {
this.customerName = customerName;
}
private void setCustomerSegment(String customerSegment) {
this.customerSegment = customerSegment;
}
private void setProductCategory(String productCategory) {
this.productCategory = productCategory;
}
@Override
public int compareTo(Order o) {
return this.id - o.getId();
}
static class OrderBuilder {
private Order order;
OrderBuilder withId(int id) {
order.setId(id);
return this;
}
OrderBuilder withPriority(String priority) {
order.setPriority(priority);
return this;
}
OrderBuilder withQuantity(float quantity) {
order.setQuantity(quantity);
return this;
}
OrderBuilder withPrice(float price) {
order.setPrice(price);
return this;
}
OrderBuilder withShipMode(String shipMode) {
order.setShipMode(shipMode);
return this;
}
OrderBuilder withCustomerName(String customerName) {
order.setCustomerName(customerName);
return this;
}
OrderBuilder withCustomerSegment(String customerSegment) {
order.setCustomerSegment(customerSegment);
return this;
}
OrderBuilder withProductCategory(String productCategory) {
order.setProductCategory(productCategory);
return this;
}
OrderBuilder createNewOrder() {
order = new Order();
return this;
}
Order build() {
return order;
}
}
}