Question

我想在Java Netbeans中使用正常的Mysql连接程序将行插入MySql数据库，但是当我运行此代码时，我的数据库仍然不受影响。我已经设置了与Netbeans和Mysql的连接，并且它工作正常。

代码：

    import java.sql.*;

    public class MySqlConnection {


       static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
       static final String DB_URL = "jdbc:mysql://localhost:3306/migration";
       static final String USER = "root";
       static final String PASS = "ngts12345";

       public static void main(String[] args) {

            Connection conn = null;

            try{
             Class.forName("com.mysql.jdbc.Driver");
             System.out.println("Connecting to a selected database...");
             conn = DriverManager.getConnection(DB_URL, USER, PASS);
             System.out.println("Connected database successfully...");
             System.out.println("Inserting records into the table...");

             String sql = "INSERT INTO document (document_id, document_name, format)" +
            "VALUES (?, ?, ?)";
             PreparedStatement preparedStatement = conn.prepareStatement(sql);
             preparedStatement.setInt(1, 1);
             preparedStatement.setString(2, "Test2");
             preparedStatement.setString(3, "Test3");
             preparedStatement.executeUpdate(); 
             preparedStatement.close();  
             conn.close();  
        }catch(SQLException se){
          //Handle errors for JDBC

       }catch(Exception e){
          //Handle errors for Class.forName

       }
     }
  }

Answer 1

format)和values

之后没有空格

将此行更改为

String sql = "INSERT INTO document (document_id, document_name, format)" +
        "VALUES (?, ?, ?)";

到

String sql = "INSERT INTO document(document_id, document_name, format) " +
        "VALUES (?, ?, ?)";

Answer 2

尝试这样做：

preparedStatement.executeUpdate(sql);

您还应该指定数据库

String sql = "INSERT INTO database_name.document (document_id, document_name, format)" +"VALUES (?, ?, ?)";

Answer 3

enter code here
try{      
Class.forName("com.mysql.jdbc.Driver"); // MySQL database  connection
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306","root","");
String sql = "select * from 'table_name'.database_name where user=? and pass=?";
  pst = conn.prepareStatement(sql);
  rs= pst.executeQuery();}

Answer 4

注意preparedStatement.executeUpdate（）返回true（记录在插入，更新或删除时成功）或false（不成功）。因此，我建议打印出结果，看它是否有效。

至于没有收到错误消息，您是否正在使用异常而不是打印错误？在catch块中，输入e.printStackTrace（）以查看错误是什么。

Java Netbeans MySql数据库连接

4 个答案: