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1.java.lang.UnsupportedClassVersionError: com/mdcchina/userinfo/logic/UserManager (Unsupported major.minor version 49.0)提示如上的错?很是郁闷
l过研究和比较在两个不同环境下的~译q行,l于发现q个主要是由于我的机子上安装?jin)两个不同版本的JDKD?我想很多的朋友在试新的JDK的时?可能不会(x)删除1.4的版?但是要注意的是要JAVA_HOME,CLASS_PATH,PATH{等的环境变量都修改成相关的JDK1.5的目录下面去,因ؓ(f)1.5相对于以前的版本的变化比较大.
2.上面的问题排除后,在运行TOMCAT5.0时候由出现?jin)如下的错?
2005-11-17 19:38:47 StandardWrapperValve[action]: Servlet.service() for servlet action threw exception
org.apache.jasper.JasperException: Unable to compile class for JSP
Generated servlet error:
C:\application\Tomcat 5.0\work\Catalina\localhost\mlinkweb\org\apache\jsp\layouts\layout_005findex_jsp.java:7: cannot access java.lang.Object
Generated servlet error:
bad class file: C:\application\Java\jdk1.5.0\jre\lib\rt.jar(java/lang/Object.class)
class file has wrong version 49.0, should be 48.0
Please remove or make sure it appears in the correct subdirectory of the classpath.
public final class layout_005findex_jsp extends org.apache.jasper.runtime.HttpJspBase
^
1 error
q个问题q是让我郁闷之极?^_^)
最后在SUN的JAVA论坛里面扑ֈ?jin)答?只要JDK1.5的LIB下面的TOOLS.JAR覆盖TOMCAT5.0目录/common/lib下面的tools.jar,然后重启TOMCAT5.0可以了(jin)
1.使用sysdOracleQ利用dbms_xdb修改端口讄
SQL> -- Change the HTTP/WEBDAV port from 8080 to 8081
SQL> call dbms_xdb.cfg_update(updateXML(
2 dbms_xdb.cfg_get()
3 , '/xdbconfig/sysconfig/protocolconfig/httpconfig/http-port/text()'
4 , 8081))
5 /
Call completed.
SQL> -- Change the FTP port from 2100 to 2111
SQL> call dbms_xdb.cfg_update(updateXML(
2 dbms_xdb.cfg_get()
3 , '/xdbconfig/sysconfig/protocolconfig/ftpconfig/ftp-port/text()'
4 , 2111))
5 /
Call completed.
SQL> COMMIT;
Commit complete.
SQL> EXEC dbms_xdb.cfg_refresh;
PL/SQL procedure successfully completed.
2.使用OEM consoleQ选择数据库,XML DatabaseQConfiguration。更改XDB的有兌|?/P>3.L数据库的初始化参敎ͼ(x) dispatchers='(PROTOCOL=TCP) (SERVICE=XDB)'Q将?x)禁止XDB的http和ftp服务
4.呵呵,当然是改变Tomcat的Port?jin)?img src ="http://www.aygfsteel.com/haoqingshi/aggbug/20187.html" width = "1" height = "1" />
下面来逐个讨论Q?BR>
一, ServletContext对象
<context-param>元素Q设?/SPAN>Context起始参数
中,(zhn)可以利?/SPAN><context-param>起始参数Q它包含两个子元素:(x)
n <param-name>起始参数名称
n <param-value>起始参数?/SPAN>
<context-param>使用在本例中W者定义了(jin)两个Context n driver_type应用E序Ʋ用的JDBC n url
有两U方式存?SPAN lang=EN-US>Context<web-app>
<context-param>
<param-name>driver_type</param-name>
<param-value>oracle.jdbc.driver.OracleDriver</param-value>
</context-param>
<context-param>
<param-name>url</param-name>
<param-value>jdbc:oracle:thin:@IP:1521:SID</param-value>
</context-param>
</web-app>
? ?/SPAN>ServletContext接口中用来存?/SPAN>Context起始参数的方?/SPAN>
Ҏ(gu)名称 |
回传cd |
?/SPAN> ?/SPAN> |
getInitParameter() |
String |
取得某个Context起始参数?/SPAN> |
getInitParameterNames() |
java.util.Enumeration |
取得所?/SPAN>Context起始参数 |
1.调用getServletConfig()ServletConfigServletConfiggetServletContext()ServletContext String url=context.getInitParameter("url");
2. getServletContext()ServletContext String url=context.getInitParameter("url");
//获得当前WebApp的\?BR> String path=context.getRealPath("/");
? ServletConfig对象
<init-param>元素Q设定init起始参数
中,(zhn)可以利?/SPAN><init-param>起始参数Q它包含两个子元素:(x)
n <init-name>起始参数名称
n <init-value>起始参数?/SPAN>
<init-param>使用在本例中W者定义了(jin)两个Config n driver_type应用E序Ʋ用的JDBC n url
在init()Ҏ(gu)中,应该Q?BR> <web-app>
<servlet>
<servlet-name>testServlet</servlet-name>
<servlet-class>com.simon.test.servlet.initparam.testServlet</servlet-class>
<init-param>
<param-name>driver_type</param-name>
<param-value>oracle.jdbc.driver.OracleDriver</param-value>
</init-param>
<init-param> <param-name>url</param-name>
<param-value>jdbc:oracle:thin:@IP:1521:SID</param-value>
</init-param>
<servlet-mapping>
<servlet-name>testServlet</servlet-name>
<url-pattern>/testServlet</url-pattern>
</servlet-mapping>
</web-app>
public void init(ServletConfig config) throws ServletException
{
//必须要承supercȝinit()Ҏ(gu)
super.init(config);
String filename=getServletConfig().getInitParameter("config-file");
//TODO
}
以上配置Q我们可以在servlet中得到其初始化信息。主要ؓ(f)以下三种Q?/P>
/*通过 getServletConfig() 获取单一?/
String value = getServletConfig().getInitParameter("name1");
/*获取所有初始化变量*/
java.util.Enumeration enum = getServletConfig().getInitParameterNames();
for (; enum.hasMoreElements(); ) {
// 获取初始化参数的名字
String name = (String)enum.nextElement();
// 获取对应?/FONT>
value = getServletConfig().getInitParameter(name);
}
/* 通过 getServletContext() 获取单一?/
String value = getServletContext().getInitParameter("name1");
以上三种方式是以前用中遇到的,现留于备忘,如果有朋友发现还有其它方式,误充,谢谢!
1.当Servlet重新定向到另外一个servlet的时?/P>
RequestDispatcher rd = request.getRequestDispatcher("secondservlet");
rd.forward(request, response);
2.当Servlet重新定向C个网늚时?/SPAN>
RequestDispatcher rd = getServletContext().getRequestDispatcher("/save.jsp");
rd.forward(request,response);
3.使用sendRedirect()Ҏ(gu),response.sendRedirect之后,应该紧跟一?return;
response.sendRedirect("index.jsp");
return ;