UC知道jsp mysql 连接异常
来源：百度知道 编辑：UC知道 时间：2024/05/14 16:59:39
登陆页面错误提示com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure Last packet sent to the server was 0 ms ago.
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HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Exception in JSP: /carslist.jsp:186
183: // Open Connection to the database
184: try{
185: Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
186: ResultSet rs = null;
187:
188: // Build SQL
189: String strsql = "SELECT * FROM `cars`";
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.J
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HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Exception in JSP: /carslist.jsp:186
183: // Open Connection to the database
184: try{
185: Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
186: ResultSet rs = null;
187:
188: // Build SQL
189: String strsql = "SELECT * FROM `cars`";
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.J
说的是数据库连接出错，下面有个空指针异常。首先是不是数据库没打开。。其次是不是数据连接写的有问题，就是数据连接的什么驱动呀还有URL USRNAME PASSWORD写的不对。检查下。。再就是程序中的问题了。。如果还没有解决建议贴全代码。。还有种可能就是你的MYsql差包。
z
空指针异常
ResultSet rs = null;
改为
ResultSet rs;
这点代码不足以诊断出错误位置