使用java程序连接到java数据库
我正在实现一个简单的教程 将java程序连接到java数据库 使用NetBeans7IDE . 这里是教程的链接使用java程序连接到java数据库,java,netbeans,Java,Netbeans,我正在实现一个简单的教程 将java程序连接到java数据库 使用NetBeans7IDE . 这里是教程的链接 http://www.homeandlearn.co.uk/java/connect_to_a_database_using_java_code.html 但当我运行该项目时,NetBeans给了我以下错误: run: java.lang.VerifyError: Constructor must call super() or this() before return in me
http://www.homeandlearn.co.uk/java/connect_to_a_database_using_java_code.html
但当我运行该项目时,NetBeans给了我以下错误:
run:
java.lang.VerifyError: Constructor must call super() or this() before return in method database_console.DBConnect.<init>()V at offset 0
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2442)
at java.lang.Class.getMethod0(Class.java:2685)
at java.lang.Class.getMethod(Class.java:1620)
at sun.launcher.LauncherHelper.getMainMethod(LauncherHelper.java:492)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:484)
Exception in thread "main" Java Result: 1
BUILD SUCCESSFUL (total time: 12 seconds)
解决此问题的任何可用建议如果您正在使用上述代码,则需要将整个代码放在课堂上
//Package declarations (if any)
//Import packages
public class className {
public static void main(String[] args) {
//Other code
}
}
您没有按照正确链接的链接进行操作
您的代码应该如下所示:
package database_console;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBConnect { // <--- This is missing from your code
public static void main(String[] args) {
try {
String host = "jdbc:derby://localhost:1527/Employees";
String uName = "faisal";
String uPass = "password";
Connection con = DriverManager.getConnection(host, uName, uPass);
} catch (SQLException err) {
System.out.println(err.getMessage());
}
} // <--- This is also missing from your code
}
package数据库_控制台;
导入java.sql.Connection;
导入java.sql.DriverManager;
导入java.sql.SQLException;
公共类DBConnect{/请将类添加到main()中
package database_console;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBConnect
{
public static void main(String[] args)
{
try
{
String host = "jdbc:derby://localhost:1527/Employees";
String uName = "faisal";
String uPass = "password";
Connection con = DriverManager.getConnection(host, uName, uPass);
}
catch (SQLException err)
{
System.out.println(err.getMessage());
}
}
}
此类用于创建数据库连接
import java.sql.Connection;
import java.sql.*;
public class GetDBConnection
{
public static Connection getConnection(String[] args)
{
String host = "jdbc:derby://localhost:1527/Employees";
String uName="faisal";
String uPass="password";
Connection con=null;
try
{
con=DriverManager.getConnection(host, uName, uPass);
}
catch ( SQLException err )
{
System.out.println( err.getMessage( ) );
}
return con;
}
}
此类用于获取并使用CooConnection
public class UseDBConnection
{
public static void main(String[] args)
{
GetDBConnection object = new GetDBConnection();
System.out.println("now you can use this DB like you want it and can create as many connection as you want");
}
}
这是你的真实代码吗(不多不少)?请发布你的全部代码(是的,不介意它是代码墙)。是的,这就是全部代码code@Luiggi门多萨:你确定你没有类定义吗?否则你的代码一开始就不会编译(也无法运行)。@PradeepSimha好的,取消删除它,我会升级它(因为你是第一个发现问题的人).但是我认为上面代码中的public clas类名是declaration@faisalabdulai,在您的代码中,既没有公共类也没有非公共类。您应该指出代码来自,而不是来自您的头顶。是的,完全正确。OP在问题中说。尝试您的建议后,现在NetBeans IDE在类声明下面加下划线使用以下消息复制类数据库\u控制台。DBConnect@faisalabdulai删除文件DBConnect.java
的全部内容,然后粘贴上面的代码。它不会给出任何编译器错误。您还有其他未显示的内容。@Faisalabdlai还会清理项目并重新生成
public class UseDBConnection
{
public static void main(String[] args)
{
GetDBConnection object = new GetDBConnection();
System.out.println("now you can use this DB like you want it and can create as many connection as you want");
}
}