java+mysql如何显示商品所有信息，显示界面如何写 具体代码

首先，需要连接到MySQL数据库并查询商品数据，可以使用JDBC来实现。以下是一个简单的Java代码示例：

import java.sql.*;

public class DisplayProducts {
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/PRODUCTS";
   static final String USER = "username";
   static final String PASS = "password";

   public static void main(String[] args) {
      Connection conn = null;
      Statement stmt = null;
      try {
         Class.forName(JDBC_DRIVER);
         conn = DriverManager.getConnection(DB_URL, USER, PASS);
         stmt = conn.createStatement();
         String sql = "SELECT * FROM products";
         ResultSet rs = stmt.executeQuery(sql);
         while(rs.next()){
            int id  = rs.getInt("id");
            String name = rs.getString("name");
            double price = rs.getDouble("price");
            String description = rs.getString("description");
            System.out.println("ID: " + id);
            System.out.println("Name: " + name);
            System.out.println("Price: $" + price);
            System.out.println("Description: " + description);
         }
         rs.close();
         stmt.close();
         conn.close();
      } catch(SQLException se) {
         se.printStackTrace();
      } catch(Exception e) {
         e.printStackTrace();
      } finally {
         try {
            if(stmt!=null) stmt.close();
         } catch(SQLException se2) {}
         try {
            if(conn!=null) conn.close();
         } catch(SQLException se) {
            se.printStackTrace();
         }
      }
   }
}

上述代码通过JDBC连接到名为PRODUCTS的MySQL数据库，查询名为products的表中的所有商品信息，并将其打印到控制台上。

至于显示界面的代码，可以使用Swing或JavaFX等图形用户界面工具包来实现。以下是一个简单的Swing代码示例：

import java.awt.*;
import java.sql.*;
import javax.swing.*;

public class ProductDisplay extends JFrame {
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/PRODUCTS";
   static final String USER = "username";
   static final String PASS = "password";

   public ProductDisplay() {
      super("Product Display");
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setLayout(new GridLayout(0, 4));
      try {
         Class.forName(JDBC_DRIVER);
         Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
         Statement stmt = conn.createStatement();
         String sql = "SELECT * FROM products";
         ResultSet rs = stmt.executeQuery(sql);
         while(rs.next()){
            int id  = rs.getInt("id");
            String name = rs.getString("name");
            double price = rs.getDouble("price");
            String description = rs.getString("description");
            JLabel idLabel = new JLabel("ID: " + id);
            JLabel nameLabel = new JLabel("Name: " + name);
            JLabel priceLabel = new JLabel("Price: $" + price);
            JLabel descriptionLabel = new JLabel("Description: " + description);
            add(idLabel);
            add(nameLabel);
            add(priceLabel);
            add(descriptionLabel);
         }
         rs.close();
         stmt.close();
         conn.close();
      } catch(SQLException se) {
         se.printStackTrace();
      } catch(Exception e) {
         e.printStackTrace();
      }
      pack();
      setVisible(true);
   }

   public static void main(String[] args) {
      new ProductDisplay();
   }
}

上述代码创建了一个Swing窗口，通过JDBC连接到名为PRODUCTS的MySQL数据库，查询名为products的表中的所有商品信息，并将其显示在窗口中。