Question

在线等！！！java连接数据库，流已关闭问题

java.sql.SQLException: 流已被关闭
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:269)
at oracle.jdbc.ttc7.LongTTCItem.getChars(LongTTCItem.java:189)
at oracle.jdbc.dbaccess.DBDataSetImpl.getCharsStreamItem(DBDataSetImpl.java:1630)
at oracle.jdbc.driver.OracleStatement.getCharsInternal(OracleStatement.java:3347)
at oracle.jdbc.driver.OracleStatement.getStringValue(OracleStatement.java:3556)
at oracle.jdbc.driver.OracleResultSetImpl.getString(OracleResultSetImpl.java:434)
at oracle.jdbc.driver.OracleResultSet.getString(OracleResultSet.java:1482)
at com.xianyifa.bbs.Theme.ThemeInfo.ThemeInfo(ThemeInfo.java:35)
at org.apache.jsp.bbs_002dxyf.show_002dposts_002dfloor.show_005fposts_005ffloor_jsp._jspService(show_005fposts_005ffloor_jsp.java:74)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
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:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
2009-3-4 15:14:55 org.apache.catalina.startup.HostConfig deployDescriptor
总是抛这个异常我的代码：
Theme T = new Theme();
T.setEmittime(rs.getTimestamp("emit_time").toString());

T.setEmitusername(rs.getString("emit_user_name"));
T.setThemematter(rs.getString("theme_matter"));
T.setThemetitle(rs.getString("theme_title"));
themeinfo.add(T);
但只要把这行注释了就没问题T.setThemematter(rs.getString("theme_matter"));最后我是把theme_matter最先读就没问题，具体什么原因不太清楚，也许数long型的缘故，它可是可以保存几G的数据类型

Answer 1

仔细查看java api文档，在ResultSet类的最上面有一段文字：

默认的 ResultSet 对象不可更新，仅有一个向前移动的指针。因此，只能迭代它一次，并且只能按从第一行到最后一行的顺序进行。

就是说ResultSet只能向前移动(rs.next())，而且只能按所取的记录的列的顺序来读取，所以这里：

String str1 = rs.getString(field1);
String str2 = rs.getString(field2);

如果所取的记录里字段field2在field1之前，而读取的时候读field2在读field1之后，那么就会抛出上述异常！！

解决方法非常简单：要么修改select语句使得field2在field1之前，要么修改读取语句的顺序！

Answer 2

package DBCONN;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;

import java.sql.SQLException;
import java.sql.Statement;

public class DatabaseConnection
{
Connection conn=null;
Statement st=null;
ResultSet rs=null;
public Connection CreateConnection()
{
try
{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
conn=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=demo","sa","");
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
catch (SQLException e)
{
e.printStackTrace();
}
return conn;
}
public ResultSet Select(String sql)
{
try
{
st=conn.createStatement();
rs=st.executeQuery(sql);
}
catch (SQLException e)
{
e.printStackTrace();
}
return rs;
}
public boolean NotSelect(String sql)
{
boolean b=false;
try
{
st=conn.createStatement();
int i=st.executeUpdate(sql);
if(i>0)
{
b=true;
}
}
catch (SQLException e)
{
e.printStackTrace();
}
return b;
}
public void Close()
{
try
{
rs.close();
st.close();
conn.close();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
}

用一下上面的代码连接数据库！！！试试！！！我都是用它的！！！很管用的！！！
但是要有jar包的！只用一个jar包就哦了！！！

Answer 3

T.setThemematter(rs.getString("theme_matter"));
好象是rs.getString的错误..
你改成rs.getLong试试
如果还不行,就看看dbaccess和java.sql的转换问题
这个,我好久没有直接和数据库打交道了,忘了,不好意思

Answer 4

java.sql.SQLException: 流已被关闭

是不是sql对象里有 单例 ？
如果没有 你获取 oracle的long话 用getInt试下

Answer 5

关闭顺序
先关闭ResultSet
再关闭statement
最后关闭connection