classpath添加在环境变量里不起作用

本文转载自 Even713 查看原文 2010/09/06 10 path/ PAT/ 环境变量/ 添加/ 环境/ class/ 变量

做李刚老师的例子：
代码：
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java



package lee;



import javax.servlet.ServletException;

import javax.servlet.ServletContext;

import javax.servlet.RequestDispatcher;

import javax.servlet.http.*;



import java.io.PrintWriter;

import java.io.IOException;

import java.sql.*;



public class LoginServlet extends HttpServlet {

    public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException {

        String errMsg = "";

        RequestDispatcher rd;//RequestDispatcher is imported

        String username = request.getParameter("username");

        String pass = request.getParameter("pass");

        try {

            DbDao dd = DbDao.instance("com.mysql.jdbc.Driver", "jdbc:mysql://localhost:3306/cara", "root", "stimpy");

            ResultSet rs = dd.query("select pass from user_table where name = '"+ username +"'");// ResultSet?

            if (rs.next()) {

                if (rs.getString("pass").equals(pass)) {

                    HttpSession session = request.getSession(true);

                    session.setAttribute("name", username);

                    rd = request.getRequestDispatcher("/welcome.jsp");//?

                    rd.forward(request, response);

                } else {

                    errMsg += "your username and password are not fit";

                }

            } else {

                errMsg += "your username does not exist, please register first";

            }

        } catch (Exception e) {

            e.printStackTrace();

        }

        

        if (errMsg != null || !errMsg.equals("")) {

            rd = request.getRequestDispatch("/login.jsp");

            request.setAttribute("err", errMsg);

            rd.forward(request, response);

        }

    }

}

编译通过：
C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"

如果我将这两个classpath添加到环境变量中，一下是我当前的环境变量：
.;E:\software\apache-tomcat-6.0.26\lib\servlet-api.jar;E:\software\apache-tomcat-6.0.26\lib\jsp-api.jar;%JAVA_HOME%/lib/tools.jar;%jJAVA_HOME%/bin

编译：
C:\Users\hp2>javac -cp "E:\software\apache-tomcat-6.0.26\lib\servlet-api.jar" "D
:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"

结果：
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:19: cannot find symbol
symbol  : class DbDao
location: class lee.LoginServlet
                        DbDao dd = DbDao.instance("com.mysql.jdbc.Driver", "jdbc
:mysql://localhost:3306/cara", "root", "stimpy");
                        ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:19: cannot find symbol
symbol  : variable DbDao
location: class lee.LoginServlet
                        DbDao dd = DbDao.instance("com.mysql.jdbc.Driver", "jdbc
:mysql://localhost:3306/cara", "root", "stimpy");
                                   ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:38: cannot find symbol
symbol  : method getRequestDispatch(java.lang.String)
location: interface javax.servlet.http.HttpServletRequest
                        rd = request.getRequestDispatch("/login.jsp");
                                    ^
3 errors

C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:38: cannot find symbol
symbol  : method getRequestDispatch(java.lang.String)
location: interface javax.servlet.http.HttpServletRequest
                        rd = request.getRequestDispatch("/login.jsp");
                                    ^
1 error

C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:38: cannot find symbol
symbol  : method getRequestDispatch(java.lang.String)
location: interface javax.servlet.http.HttpServletRequest
                        rd = request.getRequestDispatch("/login.jsp");
                                    ^
1 error

C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:38: cannot find symbol
symbol  : method getRequestDispatch(java.lang.String)
location: interface javax.servlet.ServletContext
                        rd = getServletContext().getRequestDispatch("/login.jsp"
);
                                                ^
1 error

C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:38: cannot find symbol
symbol  : method getRequestDispatch(java.lang.String)
location: interface javax.servlet.ServletContext
                        rd = getServletContext().getRequestDispatch("/login.jsp"
);
                                                ^
1 error

C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"

C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src" "D:\myWorkspace\test\WE
B-INF\src\lee\LoginServlet.java"
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:3: package javax.servlet d
oes not exist
import javax.servlet.ServletException;
                    ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:4: package javax.servlet d
oes not exist
import javax.servlet.ServletContext;
                    ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:5: package javax.servlet d
oes not exist
import javax.servlet.RequestDispatcher;
                    ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:6: package javax.servlet.h
ttp does not exist
import javax.servlet.http.*;
^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:12: cannot find symbol
symbol: class HttpServlet
public class LoginServlet extends HttpServlet {
                                  ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:13: cannot find symbol
symbol  : class HttpServletRequest
location: class lee.LoginServlet
        public void service(HttpServletRequest request, HttpServletResponse resp
onse) throws ServletException, java.io.IOException {
                            ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:13: cannot find symbol
symbol  : class HttpServletResponse
location: class lee.LoginServlet
        public void service(HttpServletRequest request, HttpServletResponse resp
onse) throws ServletException, java.io.IOException {
                                                        ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:13: cannot find symbol
symbol  : class ServletException
location: class lee.LoginServlet
        public void service(HttpServletRequest request, HttpServletResponse resp
onse) throws ServletException, java.io.IOException {

             ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:15: cannot find symbol
symbol  : class RequestDispatcher
location: class lee.LoginServlet
                RequestDispatcher rd;//RequestDispatcher is imported
                ^
D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java:23: cannot find symbol
symbol  : class HttpSession
location: class lee.LoginServlet
                                        HttpSession session = request.getSession
(true);
                                        ^
10 errors

找不到很多东西，看来是环境变量设置的问题了，麻烦大家指点一下了！！

11 个解决方案

#1

getRequestDispatch
全没加er

#2

你javahome变量设没有？

#3

设了。请忽略dispather的错误，我已经修正了。
编译时如果是这样：
C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src";"E:\software\apache-tom
cat-6.0.26\lib\servlet-api.jar";"E:\software\apache-tomcat-6.0.26\lib\jsp-api.ja
r" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"

就能编译通过。

如果把servlet-api.jar和jsp-api.jar添加到环境变量里然后这样：
C:\Users\hp2>javac -cp "E:\software\apache-tomcat-6.0.26\lib\servlet-api.jar" "D
:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"

就不通过了，是很多东西找不到。

#4

引用 2 楼 hchjjun 的回复:

你javahome变量设没有？

设了，JAVA_HOME现在是C:\Program Files (x86)\Java\jdk1.6.0_12

#5

该回复于2010-09-07 09:54:16被版主删除

#6

添加到环境变量之后，为什么还要servlet-api.jar?
C:\Users\hp2>javac -cp "D:\myWorkspace\test\WEB-INF\src" "D:\myWorkspace\test\WEB-INF\src\lee\LoginServlet.java"这样呢？

#7

环境变量直接设置成E:\software\apache-tomcat-6.0.26\lib\这样就行了

#8

classpath的那个

#9

有一点需要确认，那就是，你设置 CLASSPATH 变量之后，你的 cmd.exe 重启过了吗？

环境变量在一个进程启动之后是不会再改变了，只有重开才起作用。

#10

我现在环境变量
classpath是E:\software\apache-tomcat-6.0.26\lib\
重启了cmd窗口
依然出现上述错误。

#11

现在
classpath:E:\software\apache-tomcat-6.0.26\lib\*;这样就是指该目录下所有的jar包，可以解决。

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classpath添加在环境变量里不起作用

11 个解决方案

#1

#2

#3

#4

#5

#6

#7

#8

#9

#10

#11

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