我希望能帮助你理解这个错误。我正在建立一个与数据库的简单连接，由于某种原因它不喜欢我的输入，但我无法理解错误实际发生的位置。任何帮助将不胜感激 - 谢谢。
我的代码：
package db;
import java.sql.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
public class BankAccount {
private static String JDBC_DRIVER = "com.mysql.jdbc.Driver";
private static String DB_URL = "jdbc:mysql://localhost:3306/cs565";
private static String DB_USERNAME = "cs";
private static String DB_PASSWORD = "java";
// public String name;
// public String action;
// public double amount;
// create the table
public static void createTable(){
try
{
Class.forName(JDBC_DRIVER);
Connection conn = DriverManager.getConnection(DB_URL, DB_USERNAME, DB_PASSWORD);
Statement stmt = conn.createStatement();
String sqlDropStatement = "DROP TABLE MYTABLE_TRANSACTIONS";
try {
stmt.executeUpdate(sqlDropStatement);
}
catch (Exception e)
{
System.out.println("No old data found");
}
String sqlCreateStatement = "CREATE TABLE MYTABLE_TRANSACTIONS" +
"(TRANSACTION_ID integer auto_increment primary key," +
"ACCOUNT_ID varchar(32)," +
"TRANSACTION_TYPE varchar(32)," + "AMOUNT double)";
stmt.executeUpdate(sqlCreateStatement);
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values ('John Adams', 'initial', 100.00)";
stmt.executeUpdate(sql);
sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values ('Benjamin Franklin', 'initial', 200.00)";
stmt.executeUpdate(sql);
sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values ('George Washington', 'initial', 300.00)";
stmt.executeUpdate(sql);
sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values ('Thomas Jefferson', 'initial', 400.00)";
stmt.executeUpdate(sql);
sql = "Select * from MYTABLE_TRANSACTIONS";
ResultSet rs = stmt.executeQuery(sql);
//iterate through rows & print
while (rs.next())
{
System.out.printf("TRANSACTION_ID=%2d, ACCOUNT_ID=%8s, TRANSACTION_TYPE=%8s, AMOUNT=%8s\n",
rs.getInt("TRANSACTION_ID"),
rs.getString("ACCOUNT_ID"),
rs.getString("TRANSACTION_TYPE"),
rs.getDouble("AMOUNT"));
}
//close the connection here
stmt.close();
} catch (Exception e) {
e.printStackTrace();
}
}// end of create table method
// the deposit method
public static void makeDeposit(String name, String action, double amount){
try
{
Class.forName(JDBC_DRIVER);
Connection conn = DriverManager.getConnection(DB_URL, DB_USERNAME, DB_PASSWORD);
Statement stmt = conn.createStatement();
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values (name, action, amount)";
stmt.executeUpdate(sql);
sql = "Select * from MYTABLE_TRANSACTIONS";
ResultSet rs = stmt.executeQuery(sql);
//iterate through rows & update
while (rs.next())
{
System.out.printf("TRANSACTION_ID=%2d, ACCOUNT_ID=%8s, TRANSACTION_TYPE=%8s, AMOUNT=%8s\n",
rs.getInt("TRANSACTION_ID"),
rs.getString("ACCOUNT_ID"),
rs.getString("TRANSACTION_TYPE"),
rs.getDouble("AMOUNT"));
}
//close the connection here
stmt.close();
} catch (Exception e) {
e.printStackTrace();
}
}//********end of deposit method
// the withdrawal method
public static void makeWithdrawal(String name, String action, double amount){
try
{
Class.forName(JDBC_DRIVER);
Connection conn = DriverManager.getConnection(DB_URL, DB_USERNAME, DB_PASSWORD);
Statement stmt = conn.createStatement();
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values (name, action, amount)";
stmt.executeUpdate(sql);
sql = "Select * from MYTABLE_TRANSACTIONS";
ResultSet rs = stmt.executeQuery(sql);
//iterate through rows & update
while (rs.next())
{
System.out.printf("TRANSACTION_ID=%2d, ACCOUNT_ID=%8s, TRANSACTION_TYPE=%8s, AMOUNT=%8s\n",
rs.getInt("TRANSACTION_ID"),
rs.getString("ACCOUNT_ID"),
rs.getString("TRANSACTION_TYPE"),
rs.getDouble("AMOUNT"));
}
//close the connection here
stmt.close();
} catch (Exception e) {
e.printStackTrace();
}//********end of withdrawal method
}
public static void main(String[] args) {
//Prompt the user- what would you like to do?
// withdrawal / deposit / view balance
String name;
String action;
double amount;
createTable();
System.out.println("Please enter the name of your account: ");
Scanner input = new Scanner( System.in );
name = input.nextLine();
System.out.println("Welcome " + name);
System.out.println("What would you like to do? ");
//Deposit, Withdrawal, check balance
System.out.println("D= Deposit, W = Withdrawal, B = Show balance ");
action = input.nextLine();
//NOTE: fix this to where the letter inserts the entire word into the table
System.out.println("You chose " + action);
switch (action) {
case "D":
System.out.println("How much would you like to deposit?");
amount = input.nextDouble();
System.out.println("You selected " + amount);
makeDeposit(name, action, amount);
break;
case "W":
System.out.println("How much would you like to withdraw? ");
amount = input.nextDouble();
System.out.println("You selected " + amount);
makeWithdrawal(name, action, amount);
break;
case "B": System.out.println("You chose " + action);
// a print method here using WHERE
break;
}// end of switch
//something to bring back to the top
}
}
错误：
TRANSACTION_ID= 1, ACCOUNT_ID=John Adams, TRANSACTION_TYPE= initial, AMOUNT= 100.0
TRANSACTION_ID= 2, ACCOUNT_ID=Benjamin Franklin, TRANSACTION_TYPE= initial, AMOUNT= 200.0
TRANSACTION_ID= 3, ACCOUNT_ID=George Washington, TRANSACTION_TYPE= initial, AMOUNT= 300.0
TRANSACTION_ID= 4, ACCOUNT_ID=Thomas Jefferson, TRANSACTION_TYPE= initial, AMOUNT= 400.0
Please enter the name of your account:
George Washington
Welcome George Washington
What would you like to do?
D= Deposit, W = Withdrawal, B = Show balance
D
You chose D
How much would you like to deposit?
10.00
You selected 10.0
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'name' in 'field list'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3558)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3490)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2109)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2642)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1647)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1566)
at db.BankAccount.makeDeposit(BankAccount.java:100)
at db.BankAccount.main(BankAccount.java:187)
答案 0 :(得分：2)
绝不使用带替换的普通语句。请使用preparedStatement代替[读取：When should we use a PreparedStatement instead of a Statement?]
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values (?, ?, ?)";
PreparedStatement pstmt = connection.prepareStatement(sql);
pstmt.setString(1, name );
pstmt.setString(2, action );
pstmt.setDouble(3, amount);
pstmt.executeUpdate();
答案 1 :(得分：2)
在此行中更改make Deposit（）方法：在这种情况下，您不会传递变量，但它们将用作简单字符串。
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values(name, action, amount)";
到
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values ("+name+", "+action+", "+amount+")";
答案 2 :(得分：0)
问题来自makeDeposit()方法，特别是来自这些方面：
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values (name, action, amount)";
stmt.executeUpdate(sql);
这些值不对，你可能想要一个名为name的变量，而不是实际的字符串名称。
为了提供更多洞察力，错误是在错误发生之前运行的方法列表。顶部的那个是最新的。所以一切都从main()方法开始，该方法运行makeDeposit()方法，然后是stmt.executeUpdated(sql)调用之后的一些方法。希望能搞清楚。
答案 3 :(得分：-1)
String sql = "insert into MYTABLE_TRANSACTIONS (ACCOUNT_ID,TRANSACTION_TYPE,AMOUNT) values ('" + name + "', '" + action + "', " + amount + ")";
您需要名称和操作列的单引号，因为它们的类型为varchar，而且您还需要实际值，因此您需要使用“+”符号构建查询。
/尼克