我在 Windows 8 上使用 XAMPP。我想做的是从 Servlet 访问 MySQL 数据库。
我已将 MySQL 连接器 J jar 文件包含到 /xampp/tomcat/lib 目录中，下面是我要编译和运行的代码
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.mysql.jdbc.Driver;
public class Exercise7 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>Servlet - MySQL</title></head>");
out.println("<body>");
Connection con = null;
Statement st = null;
ResultSet rs = null;
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "";
try {
con = DriverManager.getConnection(url, user, password);
st = con.createStatement();
rs = st.executeQuery("SELECT VERSION()");
if (rs.next()) {
out.println(rs.getString(1));
}
} catch (SQLException ex) {
/*Logger lgr = Logger.getLogger(Version.class.getName());
lgr.log(Level.SEVERE, ex.getMessage(), ex);*/
out.println("Can't connect");
} finally {
try {
if (rs != null) {
rs.close();
}
if (st != null) {
st.close();
}
if (con != null) {
con.close();
}
} catch (SQLException ex) {
/*Logger lgr = Logger.getLogger(Version.class.getName());
lgr.log(Level.WARNING, ex.getMessage(), ex);*/
out.println("Can't connect");
}
}
out.println("</body></html>");
}
}
当我访问该页面时，我看到“无法连接”，这显然意味着 servlet 和 mysql 之间的连接存在问题，所以任何人都可以帮助我解决这个问题。