web项目运行中总是出现这样的问题，求高手解答！

Question

java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:24)
at s2jsp.bysj.dao.NewsDao.findNewsByID(NewsDao.java:60)
at org.apache.jsp.admin.managerNews_jsp._jspService(managerNews_jsp.java:186)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)
2012-1-9 7:18:40 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at s2jsp.bysj.dao.NewsDao.findNewsByID(NewsDao.java:61)
at org.apache.jsp.admin.managerNews_jsp._jspService(managerNews_jsp.java:186)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

Answer 1

java.lang.NullPointerException
at s2jsp.bysj.dao.NewsDao.findNewsByID(NewsDao.java:61)
看这里

Answer 2

链接失效时继续使用。validateQuery没有设定。

Answer 3

[Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
这个问题出了之后才会有java.lang.NullPointerException
at s2jsp.bysj.dao.NewsDao.findNewsByID(NewsDao.java:61)
这个问题，也就是说，下边这个问题可能是第一个问题引起的，我现在就想解决第一个问题

Answer 4

at java.sql.DriverManager.getConnection(Unknown Source)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:24)
数据库连接失败后引发的空指针异常，先检查连接是否能成功

Answer 5

数据库驱动先放下；应该先处理空指针异常：
java.lang.NullPointerException
at s2jsp.bysj.dao.NewsDao.findNewsByID(NewsDao.java:61)
再测试；

Answer 6

1.看jar有没有
2.数据库连接URL看看写错没？

Answer 7

那块应该不会有问题
public List findNewsByID (int  page)
{
News news=null;
List list=new ArrayList();
   int num=0;
 
try {
  
String sql="select top 10 * from NEWS where newsId not in (select top "+(page-1)*10+" newsId from News order by newsId desc) order by newsId desc ";

conn = BaseDao.getConn();
pstmt = conn.prepareStatement(sql);
System.out.print(sql);
rs = pstmt.executeQuery();
while (rs.next()) {
  news=new News();
  news.setNewsID(rs.getInt("newsID"));
  news.setTitle(rs.getString("title"));
            news.setContent(rs.getString("content"));
            news.setType(rs.getInt("type"));
            news.setWriterDate(rs.getString("writerDate"));
            news.setTj(rs.getInt("tj"));
            list.add(news);
}
} catch (SQLException e) {
e.printStackTrace(); 
}finally
{
this.closeAll(conn, pstmt, rs);
}
return list; }
就这个方法

Answer 8

都有的，url不会写错，因为这个问题只是偶尔出现，并不是一直是这样

Answer 9

这个conn = BaseDao.getConn();
是怎样实现的？测试下把conn做为局部变量，每次请求创建一个新的，并同步BaseDao.getConn();

Answer 10

public static Connection getConn()
{
Connection conn=null;
try {

// Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
// conn = DriverManager.getConnection("jdbc:odbc:company","sa","sa");
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1434;DataBaseName=company","sa","sa");
} catch (ClassNotFoundException e) { e.printStackTrace();
} catch (SQLException e) { e.printStackTrace();
}
return conn;
}
就是数据库的链接了

Answer 11

把这里改下：
conn = BaseDao.getConn();
if(conn == null){
    //process   
}
你上面的错误是getConn()返回了null导致
conn.prepareStatement(sql);
出现异常；

Answer 12

java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
是getConn()的异常；至于怎么解决，偶也不是很清楚，
你可以在
return conn;
时：
return conn == null ? getConn() : conn;

Answer 13

偶的理解是不是存在并发问题：
可以尝试把public static Connection getConn()
作为同步方法：
public synchronized static Connection getConn()

Answer 14

我做了如下测试：
public class BaseDao {
public final static String Driver = "";
public final static String Url = "";
public final static String Name = "";
public final static String Dbpass = "";
public   static Connection getConn()
{
Connection conn=null;
try {

Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1434;DataBaseName=company","sa","sa");
} catch (ClassNotFoundException e) { e.printStackTrace();
} catch (SQLException e) { e.printStackTrace();
}
return conn;    
} public void closeAll(Connection conn,PreparedStatement pstmt,ResultSet rs)
{
if(rs!=null)
{
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(pstmt!=null)
{
try {
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(conn!=null)
{
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

public int executeSQL(String preparedsql,String[] param)
{
Connection conn=null;
int num=0;
PreparedStatement pstmt=null;
conn=this.getConn();
String sql="";
try {
pstmt=conn.prepareStatement(sql);
num=pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}finally
{
this.closeAll(conn, pstmt, null);
}
return num;
}
public static void main(String[]args)
{   BaseDao bd=new BaseDao();

System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());
System.out.println(bd.getConn());

}

}运行这个页面
com.microsoft.jdbc.sqlserver.SQLServerConnection@c51355
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:77)
null
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:78)
null
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:79)
null
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:80)
null
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:81)
null
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:82)
null
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Connection reset
at com.microsoft.jdbc.base.BaseExceptions.createException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.base.BaseExceptions.getException(Unknown Source)
at com.microsoft.jdbc.sqlserver.tds.TDSRequest.processReply(Unknown Source)
at com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown Source)
at com.microsoft.jdbc.base.BaseConnection.open(Unknown Source)
at com.microsoft.jdbc.base.BaseDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at s2jsp.bysj.dao.BaseDao.getConn(BaseDao.java:16)
at s2jsp.bysj.dao.BaseDao.main(BaseDao.java:83)
null
com.microsoft.jdbc.sqlserver.SQLServerConnection@1855af5为什么出现这种问题呢？9次只有两个链接上

Answer 15

还有我用的是SQLServer 2005这里为什么是2000呢？

Answer 16

你不是一步步的测试发现了很多认为没有问题却有问题的地方；
如果是驱动错了，就下载SQLServer 2005的驱动jar;
替换测试就可以了；