SQL查询Java网络bean

基本上，我有一个表名java_db.Customer，其中包含CustomerID列， 姓名、地址和财务OK

基本上，我想写一个简单的查询，显示FinanceOK=true JOptionPane.ShowMessage“Finance Accepted”

否则，FinanceOK=False JOptionPane.ShowMessage“Finance谢绝”

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编写此查询的最佳方式是什么？

现在，您的帖子中有很多信息缺失，但内容不完整，下面是您如何完成此任务的方法：

long customerID_Variable = 232;   // .... whatever you have to provide customer ID number ....
String customerName = "John Doe"; // .... whatever you have to provide customer name ....
boolean financeOK = false;   // default financing approval flag
String message = "Finance Declined!"; //default message
        
// Catch SQLException if any...
try { 
    // Use whatever your connection string might be 
    // to connect to your particular Database....
    Connection conn = DriverManager.getConnection("jdbc:derby:c:/databases/salesdb jdbc:derby:salesdb");
    conn.setAutoCommit(false);
            
    // The SQL query string...
    String sql = "SELECT FinanceOK FROM Customer WHERE CustomerID = " + customerID_Variable + ";";
    // Although it is best to use the Customer ID  to reference a 
    // particular Customer you may prefer to to use the Customer
    // name and if so then use the query string below instead...
    // String sql = "SELECT FinanceOK FROM Customer WHERE Name = '" + customerName + "';";
            
    // Execute the SQL query...
    PreparedStatement stmt = conn.prepareStatement(sql);
    ResultSet rs = stmt.executeQuery();
            
    //Retrieve the data from the query result set...
    while (rs.next()) { 
        financeOK = rs.getBoolean("FinanceOK"); 
    }
            
    //Close everything...
    rs.close();
    stmt.close();
    conn.close();
} 
catch (SQLException ex) { ex.printStackTrace(); }
int msgIcon = JOptionPane.ERROR_MESSAGE;
if (financeOK) { 
    message = "Finance Accepted!"; 
    msgIcon = JOptionPane.INFORMATION_MESSAGE;
}
JOptionPane.showMessageDialog(null, message, "Financing Approval...", msgIcon);

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建议将参数值连接到SQL字符串中是一个非常非常糟糕的建议。使用占位符

？

和例如

stmt.setString（）

发送参数值。