很长一段时间以来，我一直面临着这个例外。
我的 tomcat/java Web 应用程序没有非常大的数据库事务。
我使用 MSSQL 服务器作为后端，并在 tomcat 中使用 DBCP、数据库连接池。
我有以下使用它的做法。
我的 servlet 中的数据库池。
//Skeleton
dopost
{
//geting connection using JNDI
//Creating statement object
// calling method of execution of Business Logic
}
finally
{
//closing all DB resorces
}
Business Logic
{
//do all Database transaction
}
//Original code spinet
public class Frm_mst_operation_II extends HttpServlet
{
protected void doPost(HttpServletRequest httpservletrequest, HttpServletResponse httpservletresponse) throws ServletException, IOException
{
try
{
String option=httpservletrequest.getParameter("option");
InitialContext initialcontext = new InitialContext();
if(initialcontext == null)
throw new Exception("Boom - No Context");
InitialContext initialcontext2 = new InitialContext();
if(initialcontext2 == null)
throw new Exception("Boom - No Context");
Context context = (Context)initialcontext.lookup("java:/comp/env");
Context context2 = (Context)initialcontext.lookup("java:/comp/env");
DataSource datasource = (DataSource)context.lookup(RuntimeConf.abi_database);
DataSource datasource_sql = (DataSource)context2.lookup(RuntimeConf.abi_sql_database);
if(datasource != null)
{
if(dbcon == null)
{
dbcon = datasource.getConnection();
}
else
{
if(!dbcon.isClosed())
{
dbcon.close();
}
dbcon = datasource.getConnection();
}
if(dbcon_sql == null)
{
dbcon_sql = datasource_sql.getConnection();
}
else
{
if(!dbcon_sql.isClosed())
{
dbcon_sql.close();
}
dbcon_sql = datasource_sql.getConnection();
}
if(dbcon_sql != null)
{
dbcon.setAutoCommit(false);
dbcon_sql.setAutoCommit(false);
stmt_ora1 = dbcon.createStatement();
stmt = dbcon_sql.createStatement();
if(option.equals("Insert_cge_Data"))
{
Insert_CGE_Data(httpservletrequest);
}
dbcon.close();
dbcon_sql.close();
dbcon=null;
dbcon_sql=null;
}
}
else
{
System.out.println("Data Source Not Found - Error : Exception In Frm_mst_operation_II");
}
httpservletresponse.sendRedirect(url);
}
catch(Exception exception)
{
System.out.println("Exception In Frm_mst_operation_II And Exception Is :: "+exception);
exception.printStackTrace();
}
finally
{
if(rset != null)
{
try
{
rset.close();
}
catch(SQLException e)
{
System.out.println("Exception in Frm_mst_operation_II "+e);
}
rset = null;
}
if(stmt != null)
{
try
{
stmt.close();
}
catch(SQLException e)
{
System.out.println("Exception in Frm_mst_operation_II "+e);
}
stmt = null;
}
if(stmt_ora1 != null)
{
try
{
stmt_ora1.close();
}
catch(SQLException e)
{
System.out.println("Exception in Frm_mst_operation_II "+e);
}
stmt_ora1 = null;
}
if(dbcon != null)
{
try
{
dbcon.close();
}
catch(SQLException e)
{
System.out.println("Exception in Frm_mst_operation_II "+e);
}
dbcon = null;
}
if(dbcon_sql != null)
{
try
{
dbcon_sql.close();
}
catch(SQLException e)
{
System.out.println("Exception in Frm_mst_operation_II "+e);
}
dbcon_sql = null;
}
}
}//End Of doPost() Method ...
public void Insert_CGE_Data(HttpServletRequest request) throws IOException,
ServletException, SQLException {
try
{
query_th_ora = " INSERT INTO PR_OPR_TH " + " ( "
+ " COMP_N, YR_N, TRN_N, TRN_C, "
+ " TRN_D, MCH_N, SHIFT_N, STRT_TIME, "
+ " END_TIME, PROD_N, BODY_N, "
+ " CAR_N , FIRE_N, CREATED_UID," + " CREATED_D , " +
// " UPDATED_UID, UPDATED_D" +
" TRNTYP , TOT_QTY " + " , RSN_N ) " + " VALUES " + " ( "
+ " '" + comp_cd + "', '" + yr_n + "', '" + TRN_N
+ "', 'CGE" + TRN_C + "', " + " to_date('" + trn_d
+ "', 'dd/mm/yyyy') , '" + mch_nm
+ "', '" + shift + "', to_date('" + in_time
+ "', 'dd/mm/yyyy hh:mi:ss AM'), " + " to_date('"
+ out_time + "', 'dd/mm/yyyy hh:mi:ss AM'), '" + prod_n
+ "', '" + body_n + "', " + " '" + car_n + "', '"
+ fire_n + "', '" + user_cd + "',to_date('"+ora_sysdt+"', 'dd/mm/yyyy HH24:MI:SS'), " + " 'CGE', '" + tot_qty + "'"
+ " , '"+RSN_N+"' ) " + " ";
//SQL MD20230302
query_th_sql = " INSERT INTO PROD.PR_OPR_TH " + " ( "
+ " COMP_N, YR_N, TRN_N, TRN_C, "
+ " TRN_D, MCH_N, SHIFT_N, STRT_TIME, "
+ " END_TIME, PROD_N, BODY_N, "
+ " CAR_N , FIRE_N, CREATED_UID," + " CREATED_D , " +
// " UPDATED_UID, UPDATED_D" +
" TRNTYP , TOT_QTY " + " , RSN_N, FLAG) " + " VALUES " + " ( "
+ " '" + comp_cd + "', '" + yr_n + "', '" + TRN_N
+ "', 'CGE" + TRN_C + "', " + " PROD.to_date('" + trn_d
+ "', 'dd/mm/yyyy') , '" + mch_nm
+ "', '" + shift + "', PROD.to_date('" + in_time
+ "', 'dd/mm/yyyy hh:mi:ss AM'), " + " PROD.to_date('"
+ out_time + "', 'dd/mm/yyyy hh:mi:ss AM'), '" + prod_n
+ "', '" + body_n + "', " + " '" + car_n + "', '"
+ fire_n + "', '" + user_cd + "', PROD.to_date('" + sysdt
+ "', 'dd/mm/yyyy hh:mi:ss AM'), " + " 'CGE', '" + tot_qty + "'"
+ " , '"+RSN_N_SQL+"', 'Y' ) " ;
//ORA
query_td_ora = "INSERT INTO PR_OPR_TD" + " ("
+ " COMP_N, YR_N, TRN_N, TRN_C, "
+ " TRN_D, TRNDTL_N, SRNO_C, QTY, SMPL_RMK, "
+ " OPR_N, OPRGRP_N, NXT_OPR, REJTYP_N, "
+ " REJ_QTY, STATUS, SRNO_N, DECK_NO, "
+ " CREATED_UID , CREATED_D , " +
" TRNTYP, PREV_OPR, GOOD_QTY, PREV_STATUS, "
+ " BODY_N, BARCODE_NO, PREVTRNDTL_N, PROD_N, " + "" +
" glzsrno_c, good_wt, exttrn_d," +
" glztrn_d, unit_wt, layer_n, zones_n, SOTTRN_D, ASSBLD_STS" +
" )" + " VALUES"
+ "(" + " '" + comp_cd + "', '" + yr_n + "', '" + TRN_N
+ "', 'CGE" + TRN_C + "', " + " to_date('" + trn_d
+ "', 'dd/mm/yyyy'), '" + trndtl_n + "', '" + srno_c + "', '" + accept_qty
+ "', '" + barcode_no + "', " + " '" + OPR_N + "', '"
+ OPRGRP_N + "', '" + NXT_OPR + "', '" + REJTYP_N + "', "
+ " '" + rej_qty + "', '" + status + "', '" + srno_n
+ "', '" + deck_no + "', " + " '" + user_cd
+ "', to_date('"+ora_sysdt+"', 'dd/mm/yyyy HH24:MI:SS'), "
+ " 'CGE', '" + opr_n + "', '" + good_qty + "', '"
+ PREV_STATUS + "', " + " '" + body_n + "', '"
+ barcode_no + "', '" + TRNDTL_N + "'" + " , '"+prod_n+"', " +
" '" + glzsrno_c + "', '" + good_wt + "', to_date('" + exttrn_d + "' , 'dd/mm/yyyy'), " +
" to_date('" + glztrn_d + "' , 'dd/mm/yyyy'), '" + unit_wt + "', '" + layer_n + "', " +
" '" + zones_n + "', to_date('"+SOTTRN_D+"', 'dd/mm/yyyy'),'"+ASSBLD_STS+"' " +
")";
//SQL MD20230302
query_td_sql = "INSERT INTO PROD.PR_OPR_TD" + " ("
+ " COMP_N, YR_N, TRN_N, TRN_C, "
+ " TRN_D, TRNDTL_N, SRNO_C, QTY, SMPL_RMK, "
+ " OPR_N, OPRGRP_N, NXT_OPR, REJTYP_N, "
+ " REJ_QTY, STATUS, SRNO_N, DECK_NO, "
+ " CREATED_UID , CREATED_D , " +
" TRNTYP, PREV_OPR, GOOD_QTY, PREV_STATUS, "
+ " BODY_N, BARCODE_NO, PREVTRNDTL_N, PROD_N, " + "" +
" glzsrno_c, good_wt, exttrn_d," +
" glztrn_d, unit_wt, layer_n, zones_n, FLAG, SOTTRN_D, ASSBLD_STS" +
" )" + " VALUES"
+ "(" + " '" + comp_cd + "', '" + yr_n + "', '" + TRN_N
+ "', 'CGE" + TRN_C + "', " + " PROD.to_date('" + trn_d
+ "', 'dd/mm/yyyy'), '" + trndtl_n + "', '" + srno_c + "', '" + accept_qty
+ "', '" + barcode_no + "', " + " '" + OPR_N + "', '"
+ OPRGRP_N + "', '" + NXT_OPR + "', '" + REJTYP_N_SQL + "', "
+ " '" + rej_qty + "', '" + status + "', '" + srno_n
+ "', '" + deck_no + "', " + " '" + user_cd
+ "', PROD.to_date('" + sysdt + "', 'dd/mm/yyyy hh:mi:ss AM'), "
+ " 'CGE', '" + opr_n + "', '" + good_qty + "', '"
+ PREV_STATUS + "', " + " '" + body_n + "', '"
+ barcode_no + "', '" + TRNDTL_N + "'" + " , '"+prod_n+"', " +
" '" + glzsrno_c + "', '" + good_wt + "', PROD.to_date('" + exttrn_d + "' , 'dd/mm/yyyy'), " +
" PROD.to_date('" + glztrn_d + "' , 'dd/mm/yyyy'), '" + unit_wt + "', '" + layer_n + "', " +
" '" + zones_n + "', 'Y', PROD.to_date('"+SOTTRN_D+"', 'dd/mm/yyyy'), '"+ASSBLD_STS+"' "
+")";
//System.out.println(query_th_ora);
stmt_ora1.executeUpdate(query_th_ora);
//System.out.println(query_th_sql);
stmt3.executeUpdate(query_th_sql);
//System.out.println(query_td_ora);
stmt_ora1.executeUpdate(query_td_ora);
//System.out.println(query_td_sql);
stmt3.executeUpdate(query_td_sql);
}
catch (SQLException e)
{
dbcon.rollback();
dbcon_sql.rollback();
e.printStackTrace();
}
catch (Exception e)
{
dbcon.rollback();
dbcon_sql.rollback();
e.printStackTrace();
}
}
并且在业务逻辑方法之间的一些地方我总是得到那个异常。
奇怪的是，我总是在我的 servlet 中遇到这个异常，只是在 Databean 中从来没有。
我知道为什么会引发此异常，但我不明白原因。
第二件事我的tomcat服务也间歇性地挂起。
变得完全没有响应，需要重新启动才能再次运行应用程序。
所以请你们所有人回答我的查询/问题/问题并帮助我摆脱这个泥袋。值得一提的是，我的客户端机器在 WiFi 网络上运行，这对引发此问题有影响吗？
非常感谢提前