Question

我正在使用JSP和Java，我收到错误声明无法解析DbSettings。

我已经在我的构建文件夹中创建了类DbSettings，而DbSettings.java位于我的源文件夹中。

这是stacktrace：

An error occurred at line: 53 in the jsp file: /currency_form.jsp
DbSettings cannot be resolved
50:         ResultSet rs = null;
51:         String message = null;
52:         try {
53:             rs = DbSettings
54:                     .getResultSet("SELECT BLMBG_CURR_CODE,BLMBG_CURR_NAME FROM AON_CURRENCY_SDO ORDER BY BLMBG_CURR_NAME");
55:             fEmptyRecordset = rs.first();
56:         } catch (Exception ex) {


Stacktrace:
    org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:103)
    org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:366)
    org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:476)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:378)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:353)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:340)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:657)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:357)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Java代码：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class DbSettings {
    private static Connection getConnection() throws Exception {
        Class.forName("oracle.jdbc.driver.OracleDriver");
        Connection conn = null;
        conn = DriverManager.getConnection(
                "jdbc:oracle:thin:@uschduxcls004sg08:xxxx:xxxxx",
            "xxxxx", "xxxx");
        return conn;

    }

    public static final ResultSet getResultSet(String command) throws Exception {
        Connection conn = getConnection();
        Statement stmt = null;
        stmt = conn.createStatement();
        System.out.println("Statement was Succesful");
        ResultSet rs = null;
        rs = stmt.executeQuery(command);
        System.out.println("Query was Succesful");
        return rs;

    }
}

JSP代码： //声明变量

boolean fEmptyRecordset, fFirstPass, fNeedRecordset;
        int i; // as Integer
        fEmptyRecordset = false;
        fFirstPass = true;
        fNeedRecordset = true;
        ResultSet rs = null;
        String message = null;
        try {
            rs = DbSettings
                    .getResultSet("SELECT BLMBG_CURR_CODE,BLMBG_CURR_NAME FROM AON_CURRENCY_SDO ORDER BY BLMBG_CURR_NAME");
            fEmptyRecordset = rs.first();
        } catch (Exception ex) {
            fEmptyRecordset = true;
            message = ex.getMessage();
        }
        String aMonth = "";
        int aDate, aYear;
        if ("results".compareToIgnoreCase(request.getParameter("action")) == 0) {
            aMonth = request.getParameter("selMonth");
            aDate = Integer.parseInt(request.getParameter("selDate"));
            aYear = Integer.parseInt(request.getParameter("selYear"));
        } else {
            switch (Calendar.getInstance().get(Calendar.MONTH)) {
            case Calendar.JANUARY:
                aMonth = "JAN";
            case Calendar.FEBRUARY:
                aMonth = "FEB";
            case Calendar.MARCH:
                aMonth = "MAR";
            case Calendar.APRIL:
                aMonth = "APR";
            case Calendar.MAY:
                aMonth = "MAY";
            case Calendar.JUNE:
                aMonth = "JUN";
            case Calendar.JULY:
                aMonth = "JUL";
            case Calendar.AUGUST:
                aMonth = "AUG";
            case Calendar.SEPTEMBER:
                aMonth = "SEP";
            case Calendar.NOVEMBER:
                aMonth = "NOV";
            case Calendar.DECEMBER:
                aMonth = "DEC";
            }
            aDate = Calendar.getInstance().get(Calendar.DAY_OF_MONTH);
            aYear = Calendar.getInstance().get(Calendar.YEAR);
        }
        if (message != null || fEmptyRecordset) {
            out.println("<tr><td>");
            out.println(message);
            out.println("</td></tr>");
    %>

Answer 1

检查您是否在JSP中正确导入了DBSetting类。

可以在JSP中使用import语句，但语法与普通Java略有不同。

这是page directive。 page指令可以包含所有导入包的列表。要导入多个项目，请用逗号分隔包名称，例如

一般语法：

<%@ page import="package1.myClass1,package2.myClass2,....,packageN.myClassN" %>

Answer 2

您必须使用完全限定的类名或为DBSettings类添加导入

例如。导入List类

<%@ page import="java.util.List" %>

Java类未解决的问题

2 个答案: