Java 从菜单执行SQL语句
Java新手- 尝试编写一个程序,在其中选择执行SQL语句的选项 因此,在菜单中输入1将运行 从钓鱼数据语句中选择* 但是,当我运行此命令时,SQL语句会在菜单打印之前运行。我尝试过将菜单放在许多不同的位置,甚至尝试过清理eclipse中的文件夹 任何帮助都会很好。谢谢Java 从菜单执行SQL语句,java,sql,Java,Sql,Java新手- 尝试编写一个程序,在其中选择执行SQL语句的选项 因此,在菜单中输入1将运行 从钓鱼数据语句中选择* 但是,当我运行此命令时,SQL语句会在菜单打印之前运行。我尝试过将菜单放在许多不同的位置,甚至尝试过清理eclipse中的文件夹 任何帮助都会很好。谢谢 package testingSQLstatements; import java.util.*; import java.sql.*; public class Fishdata { public static Scann
package testingSQLstatements;
import java.util.*;
import java.sql.*;
public class Fishdata {
public static Scanner scan = new Scanner(System.in);
public static int menu() {
System.out.println("1.Print all catchlog data.");
System.out.println("2.Search for a trip by season");
System.out.println("3.Print out the number of catches you have.");
System.out.println("4.Export catch log to Excel");
System.out.println("5.Display statistics");
System.out.println("5.Quit.");
System.out.println("Enter your menu choice:");
int value = scan.nextInt();
return value;
}
private static final String DATABASE_URL = "jdbc:mysql://localhost:8889/SQLStatementTest";
private static final String USERNAME = "root";
private static final String PASSWORD = "toor";
private Connection connection = null;;
private PreparedStatement selectAllFish = null;
private PreparedStatement selectBySeason = null;
private PreparedStatement insertNewTrip = null;
private PreparedStatement averageFishCaught = null;
public Fishdata() {
try {
connection = DriverManager.getConnection(DATABASE_URL, USERNAME,
PASSWORD);
selectAllFish = connection
.prepareStatement("SELECT * FROM fishingdata");
selectBySeason = connection
.prepareStatement("SELECT * FROM fishingdata WHERE season = ? ");
insertNewTrip = connection
.prepareStatement("INSERT INTO fishingdata "
+ "(season, type_of_water, type_of_bait, type_of_line, num_fish_caught ) "
+ "VALUES (?, ?, ?, ?, ?)");
averageFishCaught = connection
.prepareStatement("SELECT avg(num_fish_caught) FROM fishingdata");
} catch (SQLException sqlException) {
sqlException.printStackTrace();
System.exit(1);
}
}
public List<Fish> getAllFish() {
List<Fish> results = null;
ResultSet resultSet = null;
try {
resultSet = selectAllFish.executeQuery();
results = new ArrayList<Fish>();
while (resultSet.next()) {
results.add(new Fish(resultSet.getString("season"), resultSet
.getString("type_of_water"), resultSet
.getString("type_of_bait"), resultSet
.getString("type_of_line"), resultSet
.getInt("num_fish_caught")));
}
} catch (SQLException sqlException) {
sqlException.printStackTrace();
} finally {
try {
resultSet.close();
} catch (SQLException sqlException) {
sqlException.printStackTrace();
close();
}
}
return results;
}
public List<Fish> getSelectBySeason(String name) {
List<Fish> results = null;
ResultSet resultSet = null;
try {
selectBySeason.setString(1, name);
resultSet = selectBySeason.executeQuery();
results = new ArrayList<Fish>();
while (resultSet.next()) {
results.add(new Fish(resultSet.getString("season"), resultSet
.getString(" type_of_water"), resultSet
.getString(" type_of_bait"), resultSet
.getString(" type_of_line"), resultSet
.getInt("num_fish_caught")));
}
} catch (SQLException sqlException) {
sqlException.printStackTrace();
} finally {
try {
resultSet.close();
} catch (SQLException sqlException) {
sqlException.printStackTrace();
close();
}
}
return results;
}
public int addFish(String season, String type_of_water,
String type_of_bait, String type_of_line, int num_fish_caught) {
int result = 0;
try {
insertNewTrip.setString(1, season);
insertNewTrip.setString(2, type_of_water);
insertNewTrip.setString(3, type_of_bait);
insertNewTrip.setString(4, type_of_line);
insertNewTrip.setInt(5, num_fish_caught);
result = insertNewTrip.executeUpdate();
}
catch (SQLException sqlException) {
sqlException.printStackTrace();
close();
}
return result;
}
public void close() {
try {
connection.close();
}
catch (SQLException sqlException) {
sqlException.printStackTrace();
}
}
}
实际上,您并没有在代码中的任何地方调用menu方法。下面的代码是运行应用程序的主代码的示例。请注意,使用枚举可能比使用像这样的幻数更好,但这只是一个示例
public static void main (String[] args) {
Fishdata fishdata = new Fishdata();
int choice = menu();
switch (choice) {
case 1:
System.out.println(fishdata.getAllFish()); // or whatever you want to do with the list
break;
case 2:
// etc.
default:
break;
}
}
我一点也没有出错。它只是直接连接到数据库并执行SELECT语句。我试图让它在执行任何操作之前等待我从菜单中的输入。你的公共静态无效字符串[]args代码在哪里?你如何调用这个类?