JDBC连不上oracle了

Question

控制台提示：
java.sql.SQLException: Io 异常: The Network Adapter could not establish the connection
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:145)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:190)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:363)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:401)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:441)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:165)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:839)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at wf.common.DBUtil.getConnection(DBUtil.java:16)
at wf.traffic.TrafficBP.getCarnumber(TrafficBP.java:17)
at wf.traffic.TrafficServlet.doGet(TrafficServlet.java:26)
at wf.traffic.TrafficServlet.doPost(TrafficServlet.java:34)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Unknown Source)页面上是exception java.lang.NullPointerException
wf.traffic.TrafficBP.getCarnumber(TrafficBP.java:41)
wf.traffic.TrafficServlet.doGet(TrafficServlet.java:26)
wf.traffic.TrafficServlet.doPost(TrafficServlet.java:34)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

Answer 1

我上午还好用的 下午就不行了
驱动程序类DBUtil
public class DBUtil { public static Connection getConnection() {
Connection con = null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
String url = "jdbc:oracle:thin:@132.238.76.188:1521:orcl";
String user = "icd";
String pwd = "icd";
con = DriverManager.getConnection(url, user, pwd);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return con;
}
}

Answer 2

public class TrafficBP {
public List getCarnumber(TrafficBean dto){
List list=new ArrayList();
Connection con = DBUtil.getConnection();
String sql="select c.cpzh ,a.wzsj,b.name,a.yxbz from peccancy a , "+
 " vehicle c , standernote b  where  c.cpzh='"+dto.getCarnumber()+"' and c.hpzl='"+dto.getArea()+
  "'and (substr(a.wzdd,1,5)=b.id) and c.cpz_sn=a.cpz_id order by a.wzsj desc";
System.out.println(sql);
try {
PreparedStatement ps=con.prepareStatement(sql.toString());

ResultSet rs=ps.executeQuery();


while(rs.next()){
TrafficBean x=new TrafficBean();
x.setCpzh(rs.getString("cpzh"));
x.setWzsj(rs.getString("wzsj"));
x.setName(rs.getString("name"));
x.setYxbz(rs.getString("yxbz"));
System.out.println("a");
list.add(x);
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return list;
}
}

Answer 3

Servlet代码是
public class TrafficServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String number=CharTools.isoToUTF(request.getParameter("number"));
String area=request.getParameter("area");

TrafficBean dto=new TrafficBean();
dto.setCarnumber(number);
dto.setArea(area);
TrafficBP bp=new TrafficBP();

request.setAttribute("datas",bp.getCarnumber(dto));

request.getRequestDispatcher("/query.jsp").forward(request,response);

}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}}

Answer 4

wf.traffic.TrafficBP.getCarnumber(TrafficBP.java:41) 
这行出现空指针异常。
把驱动包再重新导下试试。

Answer 5

先用个应用程序看你可以连上你的数据库不?
我怀疑是数据库down掉了

Answer 6

package com.svse.util;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class DBCon {
private static String driver = "oracle.jdbc.driver.OracleDriver";
private static String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
private static String user = "scott";
private static String password = "tiger";

public static Connection getConnection(){
try {
Class.forName(driver);
Connection con=DriverManager.getConnection(url, user, password);
System.out.println("ok");
return con;
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}

public static void close(Connection con,Statement stm,ResultSet rs){
if(con!=null){
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(stm!=null){
try {
stm.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

public static void main(String[] args) {
DBCon.getConnection();
}
}给你例子  拷过去看看

Answer 7

先pin一下数据库是否down掉了。

Answer 8

估计是 Oracle 服务停掉了

Answer 9

1.确保你和你的数据库服务器之间的网络是通畅的，比如ping一下。
2.确保你的服务器启动oracle服务了。

Answer 10

The Network Adapter could not establish the connection 有个服务没开啊。

Answer 11

首先测试一下端口
cmd telnet localhost 1521 如果只看见光标在最左上角就通了
记得导入驱动 classes12.jar
然后好好的配置你的连接
/**
 *打开连接方法
 */
public Connection openConn() { try {
Class.forName("oracle.jdbc.driver.OracleDriver"); return DriverManager.getConnection(
"jdbc:oracle:thin:@localhost:1521:ACCP", "scott", "tiger");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} }
        //测试一下 如果打印了连接地址姐连接好了
public static void main(String[] args) { System.out.println(new TestConn().openConn()); }

Answer 12

The Network Adapter could not establish the connection 
指的是 网络适配器无法建立连接
检查端口通了没 再看看连接字符串
jdbc:oracle:thin:@localhost:1521:数据库名", "scott", "tiger");