java.sql导入不起作用 [英] java.sql import not working

问题描述

我的.getTables和.prepareStatement无法正常工作.我以为只需要导入java.sql.*即可使它们起作用.请让我知道我还需要做什么.感谢您的时间.这两行旁边都显示找不到符号"，将无法编译.

My .getTables and .prepareStatement are not working. I thought I only had to import the java.sql.* for these to work. Please let me know what else I need to do. Thank you for your time. It says "cannot find symbol" next to both lines and will not compile.

import edu.lcc.citp.inventory.Product;
import java.sql.DriverManager;
import javax.jms.Connection;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import javax.jms.JMSException;

public class DatabaseProductDao implements DataAccessObject<Product> {

Connection con;

public DatabaseProductDao() throws SQLException, JMSException, ClassNotFoundException {

    Class.forName("cockeb.org.apache.derby.jdbc.ClientDriver");

    try (Connection con = (Connection) DriverManager.getConnection("jdbc:derby://localhost:1527/store;create=true")) {
        boolean exists = con.getMetaData().getTables(null, null, "PRODUCT", null).next();
        if (exists) {
            System.out.println("Table Exists");
        } else {
            String createDml = "CREATE TABLE PRODUCT (UPC VARCHAR(25), SHORT_DETAILS VARCHAR(50), LONG_DETAILS VARCHAR(5000), PRICE DECIMAL(10,2), STOCK INTEGER, PRIMARY KEY (UPC))";
            PreparedStatement createStatement =     con.prepareStatement(createDml);
            createStatement.execute();
        }
    } catch (SQLException e) {
        System.out.println("Can Not Connect At This Time");
    }
}

推荐答案

问题与导入有关. 您导入了javax.jms.Connection，这是绝对错误的.只需删除它即可. 您想要的是java.sql(java.sql.Connection)包中的Connection类.

The problem is with imports. You imported javax.jms.Connection which is obiously wrong. Just delete it. What you wanted is Connection class from java.sql (java.sql.Connection) package.

我也不建议在导入中使用通配符(.*)，而是选择您实际使用的特定类.对于您的情况:

Also I do not suggest to use wildcards (.*) in import but pick specific class you actually use. In your case:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

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