Java 数据库查询中出现错误
我正在尝试通过Java程序在MySql中创建表。在创建表的数据库查询中似乎有一个错误,我无法理解。这是我的java程序Java 数据库查询中出现错误,java,mysql,sql,jdbc,Java,Mysql,Sql,Jdbc,我正在尝试通过Java程序在MySql中创建表。在创建表的数据库查询中似乎有一个错误,我无法理解。这是我的java程序 package Registration; import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.sql.ResultSet; import java.sql.SQLException; public class S
package Registration;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class StartBatch
{
public void startBatch(String batch)
{
Connection connection=null;
String connectionURL = "jdbc:mysql://localhost:3306/Batches";
Statement stmt;
ResultSet rs1;
try
{
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(connectionURL, "root", "");
stmt=connection.createStatement();
rs1=stmt.executeUpdate("CREATE TABLE IF NOT EXISTS `"+batch+"` (\n" +" `id` int(11) NOT NULL AUTO_INCREMENT,\n" +" `student` text NOT NULL,\n" +" `fees` bigint(20) NOT NULL,\n" +" PRIMARY KEY (`id`)\n" +") ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;");
//The error is in above query
}
catch(ClassNotFoundException e){
e.printStackTrace();
}
catch(SQLException e){
e.printStackTrace();
}
catch (Exception e){
e.printStackTrace();
}
finally {
// Always close the database connection.
try {
if (connection != null) connection.close();
}
catch (SQLException ignored){
}
}
}
}
错误:
java.lang.RuntimeException: Uncompilable source code - incompatible types: int cannot be converted to java.sql.ResultSet
at Registration.StartBatch.startBatch(StartBatch.java:39)
at org.apache.jsp.CreatedBatch_jsp._jspService(CreatedBatch_jsp.java:83)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
我正在使用Netbeans来运行这个类 试试这个:
int updt;
updt=stmt.executeUpdate("CREATE TABLE IF NOT EXISTS " + batch + " (id int(11) NOT NULL AUTO_INCREMENT, student text NOT NULL, fees bigint(20) NOT NULL, PRIMARY KEY (id)) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1");
首先
executeUpdate()
用于插入、删除和更新
查询,因此您不应将其用于创建表
如果要使用of语句或
返回类型为void的PreparedStatement
(主要推荐)
此外,您的
stmt.executeUpdate(query)
返回int
type notResultSet
类型请通过添加stacktrace。请发布您收到的错误如果您不添加stacktraceconnection=DriverManager.getConnection之类的额外信息,则无法知道发生了什么(connectionURL,“root”和“”);MySQL数据库的密码在哪里?.MySQL数据库不允许您执行任何操作,除非您输入了有效的passwordstatement.executeUpdate不返回结果集,而是返回int