我想在数据库中进行普通插入，或者只是选择一个。但是我做不到，总是有一个错误。
Caused by: org.sqlite.SQLiteException: [SQLITE_ERROR] SQL error or missing database (near "ScientistRick": syntax error)
at org.sqlite.core.DB.newSQLException(DB.java:941) ~ [spigot.jar:git-Spigot-518206a-a5b9c7b]
我一直都在修改代码，但是我经验不足，因此一无所获...
在下面您可以看到我的三个班级。我不知道什么可能重要，所以我在这里插入了所有内容。
以下是选择和插入的方法：
package de.elektriker_lifestyle.reducedcoffee;
import java.io.File;
import java.sql.*;
import java.util.Date;
public class sqlite {
static String url = ReducedCoffee.getInstance().pathOfPlayerDataURL;
/**
* Connect to a sample database
*/
public static String createNewDatabase() throws SQLException{
String result = "";
String sql = "CREATE TABLE IF NOT EXISTS playerJoins (\n"
+ " primkey integer PRIMARY KEY AUTOINCREMENT,\n"
+ " player_name text NOT NULL,\n"
+ " player_uuid text NOT NULL,\n"
+ " last_login INT NOT NULL,\n"
+ " player_streak integer DEFAULT 0 NOT NULL\n"
+ ");";
Statement stmt = null;
Connection connection = DriverManager.getConnection(url);
stmt = connection.createStatement();
stmt.executeUpdate(sql);
stmt.close();
createInitialTable();
return result;
}
public static void createInitialTable() throws SQLException{
// SQL statement for creating a new table
String sql = "CREATE TABLE IF NOT EXISTS playerJoins (\n"
+ " primkey integer PRIMARY KEY AUTOINCREMENT,\n"
+ " player_name text NOT NULL,\n"
+ " player_uuid text NOT NULL,\n"
+ " last_login INT NOT NULL,\n"
+ " player_streak integer DEFAULT 0 NOT NULL\n"
+ ");";
Statement stmt = null;
Connection connection = DriverManager.getConnection(url);
stmt = connection.createStatement();
stmt.executeUpdate(sql);
stmt.close();
}
/**
* insert data into a table
*
* @param path the database path
* @param tableName name of the table
* @param columnNames the column names in a comma separated format like value1, value2, value2
* @param data the data in a comma separated format, strings must be surrounded by apostrophe like value1, 'string1', value2
*/
public static void insertData(String path, String tableName, String columnNames, String data) {
String sql = "INSERT INTO " + tableName + " (" + columnNames + ") VALUES(" + data + ")";
}
/**
* select specific data from a table
*
* @param path the database path
* @param tableName name of the table
* @param selectedColumns the column names which should be selected like "name, date, age"
* @param whereStatement the complete where statement like "name = "Peter" AND age = 80"
*/
public static void selectData(String path, String tableName, String selectedColumns, String whereStatement) throws SQLException {
}
public static boolean checkIfPlayerExists(String uuid, String name) throws SQLException {
String sql = "SELECT COUNT(*) FROM playerJoins WHERE player_uuid = '" + uuid + " AND player_name='" + name + "'";
Statement stmt = null;
Connection connection = DriverManager.getConnection(url);
stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(sql);
boolean result = (rs.getInt(1) > 0) ? true : false;
return result;
}
public static void insertPlayer(String uuid, String name) throws SQLException {
Date currentDate = new Date();
long unixTime = currentDate.getTime() / 1000;
// SQL statement for creating a new table
String sql = "INSERT INTO playerJoins (player_uuid, player_name, last_login) VALUES (\"770e9bb2-ff36-4229-b5c0-ab9f5adb8b2f\",\"ScientistRick\",1111);";
Statement stmt = null;
Connection connection = DriverManager.getConnection(url);
stmt = connection.createStatement();
stmt.executeUpdate(sql);
stmt.close();
}
}
这里我使用选择方法：
package de.elektriker_lifestyle.reducedcoffee;
import org.bukkit.Bukkit;
import org.bukkit.event.Listener;
import java.io.IOException;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Date;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.player.PlayerJoinEvent;
public class joinEvent implements Listener {
@EventHandler
public void onPlayerJoin(PlayerJoinEvent event) throws SQLException {
Player p = event.getPlayer();
String uuid = p.getUniqueId().toString();
String name = p.getDisplayName();
Bukkit.broadcastMessage("§4DEBUG-MESSAGE: " + uuid + " | " + name);
ReducedCoffee plugin = ReducedCoffee.getInstance();
if(sqlite.checkIfPlayerExists(uuid, name)) {
Bukkit.broadcastMessage("§9 Player existiert!");
} else {
Bukkit.broadcastMessage("§9 Player existiert noch nicht!");
sqlite.insertPlayer(uuid, name);
Bukkit.broadcastMessage("§9 Player wurde nun hinzugefügt!");
}
}
}
如果插件类很重要，我不知道...如果不需要，请删除！
package de.elektriker_lifestyle.reducedcoffee;
import org.bukkit.Bukkit;
import org.bukkit.plugin.java.JavaPlugin;
import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class ReducedCoffee extends JavaPlugin {
static boolean debugModeIsEnabled = false;
// useful plugin information
String pathOfPlugin = getDataFolder().getAbsolutePath();
String pathOfPlayerData = pathOfPlugin + "/" + "playerData.db";
String pathOfPlayerDataURL = "jdbc:sqlite:" + pathOfPlayerData;
// creates the possibility to access the plugin instance
public static ReducedCoffee getInstance() {
return (ReducedCoffee) Bukkit.getPluginManager().getPlugin("ReducedCoffee");
}
// happens when the plugin gets loaded during the server-start
@Override
public void onEnable(){
new File(pathOfPlugin).mkdirs();
try {
String message = sqlite.createNewDatabase();
} catch (SQLException e) {
getLogger().info("SQL-Fehler: " + e);
}
getServer().getPluginManager().registerEvents(new joinEvent(), this);
}
}
我真的不知道为什么，Statemnet是绝对正确的。使用SQLite数据库管理程序，我的语句可以完美运行...