Java-越界異常數據庫

Question

我在學期開始之前正在練習Java，並且嘗試創建將在指定的CSV文件中讀取的代碼，並使用它創建數據庫。 但是我得到一個錯誤，說

“線程“主”中的異常” java.lang.ArrayIndexOutOfBoundsException：3
在LoadData.main（LoadKids.java:52）“

我的代碼在下面列出。
該行的錯誤是“ Rating = fields [3] .trim（）;”

import java.io.File;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;


public class LoadData {

public static void main(String[] args) {
    Connection c = null;
    Statement s = null;
    Scanner fromFile = null;
    String sql1 = null, sql2 = null;
    String line = null, ID = null, Console = null, Title = null, Rating = null, Multiplayer = null;
    String[ ] fields;

    try {
        // Define Connection and Statement objects.
        Class.forName("org.sqlite.JDBC");
        c = DriverManager.getConnection("jdbc:sqlite:games.db");
        s = c.createStatement();

        // Instantiate scanner to read from file.
        fromFile = new Scanner(new File ("FileName.csv"));

        // Create the table.
        sql1 = "create table if not exists " +
            "games(gameid integer, " +
            "ID varchar(2), " +
            "Console varchar(15), " +
            "Title varchar(20), " +
            "Rating varchar(2), " +
            "Multiplayer varchar(3));";
        System.out.println("sql1: " + sql1);
        s.executeUpdate(sql1);

        // Read and throw away header line.
        fromFile.nextLine( );

        // Populate the table.
        for (int id = 1001; fromFile.hasNextLine( ); id++) {
            line = fromFile.nextLine( );
            fields = line.split(" ");
            ID = fields[0].trim();
            Console = fields[1].trim();
            Title = fields[2].trim();
            Rating = fields[3].trim();
            Multiplayer = fields[4].trim();
            sql2 = String.format(
                "insert into games (gameid, ID, Console, Title, Rating, Multiplayer) " +
                "values (%d, '%s', '%s', '%s', '%s', '%s');", 
                id, ID, Console, Title, Rating, Multiplayer);
            System.out.println(sql2);
            s.executeUpdate(sql2);
        }
        c.close( );
    }
    catch (FileNotFoundException e) {
        System.out.println("File queries.sql not found.");
        System.err.println( e.getClass().getName() + 
            ": " + e.getMessage() );
    }
    catch(SQLException e) {
        System.out.println("SQLException.");
        System.err.println( e.getClass().getName() + 
            ": " + e.getMessage() );
    }
    catch (ClassNotFoundException e ) {
        System.err.println( e.getClass().getName() + 
            ": " + e.getMessage() );
    }
    finally {
        fromFile.close( );
    }
}
}

Answer 1

請將數據發布到您的csv文件中。 通常，CSV文件用逗號分隔，因此名稱用逗號分隔。 但是，您的代碼使用空格分隔值。

fields = line.split(" ");

如果您的CSV數據確實用逗號分隔，請將該行更改為

fields = line.split(",");

如果您的CSV數據用空格分隔，請確認文件中的每一行至少有5個項目用空格分隔。