我正在尝试将我的tic tac toe游戏结果输出到数据库。但是，只要两个客户端之间的匹配完成，我就会遇到此错误。这是我的服务器端代码的摘录和错误消息：
数据库类：
import java.sql.*;
import java.util.*;
import javax.swing.JOptionPane;
class Database {
final String JDBC_DRIVER = "org.apache.derby.jdbc.ClientDriver";
final String DB_URL = "jdbc:derby://localhost:1527/Mini Project";
// Database credentials
final String USER = "Joe";
final String PASS = "plateau";
Connection conn;
Statement stmt;
public Database() {
try {
Class.forName("org.apache.derby.jdbc.ClientDriver");
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
//STEP 4: Execute a query
System.out.println("Creating statement...");
stmt = (Statement) conn.createStatement();
} catch (SQLException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
}
}
public User getUser(String userName) {
User user = null;
try {
ResultSet resultSet = stmt.executeQuery("SELECT * FROM PLAYERS");
while (resultSet.next()) {
//Retrieve by column name
user = new User(resultSet.getInt(1),
resultSet.getString(2),
resultSet.getString(3),
resultSet.getString(4),
resultSet.getString(5),
resultSet.getString(6));
}
resultSet.close();
} catch (SQLException ex) {
ex.printStackTrace();
System.err.println(ex.toString());
}
return user;
}
public Boolean insertPlayer(User player) {
Boolean isAdded = false;
int DUPLICATE_PRIMERY_KEY_ERROR_CODE = 1062;
String sql = "INSERT INTO PLAYERS(Name,Surname,Username,Password,Email) VALUES('"
+ player.getName() + "','" + player.getSurname() + "','" + player.getUsername() + "','"
+ player.getPassword() + "','" + player.getEmail() + "','"
+ "','" + "');";
try {
stmt.execute(sql);
isAdded = true;
} catch (SQLException ex) {
isAdded = false;
ex.printStackTrace();
System.err.println(ex.toString());
if (ex.getErrorCode() == DUPLICATE_PRIMERY_KEY_ERROR_CODE) {
JOptionPane.showMessageDialog(null, "Username with or email already exist");
}
}
return isAdded;
}
public void insertGameResult(Results result) {
String igr = "INSERT INTO RESULTS(Name1, Surname1, Name2, Surname2, Winner) VALUES('"
+ result.getName1() + "','" + result.getSurname1() + "','" + result.getName2() + "','"
+ result.getSurname2() + "','" + result.getWinner() + "');";
try {
Boolean added = stmt.execute(igr);
if (added) {
JOptionPane.showMessageDialog(null, "Result added successfuly");
}
} catch (SQLException ex) {
ex.printStackTrace();
System.err.println(ex.toString());
}
}
}
玩家类：
class Player extends Thread {
Socket insocket;
Socket outSocket;
public Player(Socket sock, Socket opnSock) {
this.insocket = sock;
this.outSocket = opnSock;
}
@Override
public void run() {
try {
while (true) {
InputStream is = insocket.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String readData = br.readLine();
OutputStream os = outSocket.getOutputStream();
PrintWriter pw = new PrintWriter(os, true);
pw.println(readData);
// logTextArea.append(Rdata + "\n");
if (readData.contains("winner*")) {
String[] splitData = readData.split(",");
String player1 = splitData[1];
String player2 = splitData[2];
int winner = Integer.valueOf(splitData[3]);
win += 1;
if (win == 2) {
saveResult(player1, player2, winner);
if (winner == 1) {
winner = 2;
} else if (winner == 2) {
winner = 1;
}
saveResult(player2, player1, winner);
win = 0;
}
}
}
} catch (Exception ex) {
ex.printStackTrace();
jtaLog.append(ex.toString() + "\n");
}
}
}
主类下的保存结果方法：
public void saveResult(String username1, String username2, int winner) {
User p1 = database.getUser(username1);
User p2 = database.getUser(username2);
Results result = new Results(0, p1.getName(), p1.getSurname(), p2.getName(), p2.getSurname(), winner);
database.insertGameResult(result);
}
以下是我收到的错误消息：
java.sql.SQLSyntaxErrorException: Syntax error: Encountered ";" at line 1, column 98.
at org.apache.derby.client.am.SQLExceptionFactory.getSQLException(Unknown Source)
at org.apache.derby.client.am.SqlException.getSQLException(Unknown Source)
at org.apache.derby.client.am.ClientStatement.execute(Unknown Source)
at tictactoeserver.Database.insertGameResult(Database.java:106)
at tictactoeserver.TicTacToeServer.saveResult(TicTacToeServer.java:200)
at tictactoeserver.TicTacToeServer$Player.run(TicTacToeServer.java:317)
Caused by: ERROR 42X01: Syntax error: Encountered ";" at line 1, column 98.
at org.apache.derby.client.am.ClientStatement.completeSqlca(Unknown Source)
at org.apache.derby.client.am.ClientStatement.completeExecuteImmediate(Unknown Source)
at org.apache.derby.client.net.NetStatementReply.parseEXCSQLIMMreply(Unknown Source)
at org.apache.derby.client.net.NetStatementReply.readExecuteImmediate(Unknown Source)
at org.apache.derby.client.net.StatementReply.readExecuteImmediate(Unknown Source)
at org.apache.derby.client.net.NetStatement.readExecuteImmediate_(Unknown Source)
at org.apache.derby.client.am.ClientStatement.readExecuteImmediate(Unknown Source)
at org.apache.derby.client.am.ClientStatement.flowExecute(Unknown Source)
at org.apache.derby.client.am.ClientStatement.executeX(Unknown Source)
... 4 more
java.sql.SQLSyntaxErrorException: Syntax error: Encountered ";" at line 1, column 98.
遇到了什么“;”是什么意思，我该怎么做才能纠正它？
答案 0 :(得分：8)
Encountered ";"是什么意思，我该怎么做才能纠正它？
这意味着您的SQL语句有一个额外的;字符，而SQL解析器并不期望这个字符。虽然通常在交互式SQL shell中使用;终止SQL命令，但在通过JDBC执行SQL命令时，不得添加它们。
在您的情况下，在INSERT语句中，删除尾随;，例如insertPlayer()方法：
...
+ "','" + "');";
^
您的insertGameResult()方法也是如此（这是堆栈跟踪实际显示的方法）：
...
+ result.getSurname2() + "','" + result.getWinner() + "');";
^
另外，作为附加说明，在构建SQL语句时不要使用字符串连接。这使得语句易受SQL injections的攻击。改为使用绑定变量。