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过去2-3天我遇到了一个问题。这似乎是一个小问题，但我一直无法抓住它。java中的突变结果集行为
问题在于代码中的resultset rs。 方法mergeTable中的while（rs.next（））语句行为突然。这是第一次，在某些情况下，它会进入while循环，有时它不会，并且在某些情况下，当它进入while循环时，会突然抛出结果集耗尽异常。我搜索了一下，发现结果集可能已经被访问代码的其他线程关闭了。但是这是一个简单的独立Java应用程序，不是多线程的。
我也在照顾其他两个resultset，check和checktarget不会影响resultset rs。我正在关闭语句和结果集。 你可以看看代码，看看我是否错过了某些东西。
正在使用的两个数据库实例是10.180.22.93:1521:V3demo（称为源数据库）和10.180.22.93:1521:fusiondb（称为目标数据库）。 rs结果集来自源数据库。结果集检查和检查目标来自目标数据库。因此，结果集rs将来自源数据库的表A，结果集检查和checktarget将来自目标数据库的表A.
static String mergeTable() throws Exception {
String result = "ERROR";
int error = 0;
String tableString = "<table " + tablename + ">";
PreparedStatement preparedSelect = null;
PreparedStatement preparedSelectTarget = null;
Statement selectSourceStmt = null;
ResultSet checkTarget = null;
ResultSet rs = null;
try {
logger.println("====================================================================================");
logger.println("Processing table:" + tablename);
System.out.println("====================================================================================");
System.out.println("Processing table:" + tablename);
// Create query to fetch records from the source
String sourceQuery = "SELECT * FROM " + tablename;
if (owner.trim().equals("F1") || owner.trim().equals("C1") || owner.trim().equals("CM"))
sourceQuery = sourceQuery + " WHERE OWNER_FLG='" + owner + "'";
// Get the result set
selectSourceStmt = source.createStatement();
rs = selectSourceStmt.executeQuery(sourceQuery);
System.out.println(sourceQuery);
String selectSQL = "SELECT COUNT(*) FROM " + tablename + " WHERE ";
String selectSQLTarget = "SELECT * FROM " + tablename + " WHERE "; // ankush
ResultSetMetaData metaData = rs.getMetaData();
List list = new ArrayList();
List typesList = new ArrayList();
for (int i = 1; i <= metaData.getColumnCount(); i++) {
String columnName = metaData.getColumnName(i);
list.add(columnName); // list contains the entire list of columns of the source
typesList.add(metaData.getColumnType(i));
}
for (int i = 1; i < keys.length; i++) {
if (i == 1) {
selectSQL = selectSQL + " " + keys[i] + "= ?";
selectSQLTarget = selectSQLTarget + " " + keys[i] + "= ?"; //ankush
}
else {
selectSQL = selectSQL + " AND " + keys[i] + "= ?";
selectSQLTarget = selectSQLTarget + " AND " + keys[i] + "= ?"; //ankush
}
}
logger.println("Select SQL:" + selectSQL);
logger.println("selectSQLTarget:" + selectSQLTarget); //ankush
preparedSelect = target.prepareStatement(selectSQL);
preparedSelectTarget = target.prepareStatement(selectSQLTarget); //ankush
int updateCount = 0, insertCount = 0, errorCount = 0;
// rs contains the entire table snapshot of source based on the owner flag
if (rs != null) {
while (rs.next()) {
try {
int i, count;
// check if record exists or not; keys contain the values of primary columns specified in the.lst file
for (int j = 1; j < keys.length; j++) {
preparedSelect.setObject(j, rs.getObject(keys[j])); // for every single row in source, corresponding rows are fetched from target.Here, where clause is being prepared
}
ResultSet check = preparedSelect.executeQuery(); // check is the target resultset for the primary key values in current row of source resultset
check.next();
count = check.getInt(1); // count gives the row/s fetched from target based on the values in source.
check.close();
// check if record exists or not; keys contain the values of primary columns specified in the.lst file
for (int j = 1; j < keys.length; j++) {
// for every single row in source, corresponding rows are fetched from target.Here, where clause is being prepared
preparedSelectTarget.setObject(j, rs.getObject(keys[j]));
}
// check is the target resultset for the primary key values in current row of source resultset
checkTarget = preparedSelectTarget.executeQuery();
checkTarget.next();
// if record exists UPDATE CONDITION
if (true) { // if there is a record in target for a row in source, update target
String rowString = "<row>";
String rowDiffFlag = "N";
// if merge flag is Y
if (mergeFlag.equals("Y")) {
String colDiffFlag = "";
String sourceColVal = "";
String targetColVal = "";
// list contains the column names
for (i = 0; i < list.size(); i++) {
System.out.println("value of i " + i);
}
i++; // ?????
} else {
logger.print("Did not update Record:");
}
rowString = rowString + "</row>";
if (rowDiffFlag.equals("Y")) {
tableString = tableString + rowString;
}
} else { // if there is no record in target for a row in source, insert into target
String sourceColVal = "";
String rowString = "<row>";
for (i = 0; i < list.size(); i++) { //looping through columns in a row
System.out.println("column " + i);
}
rowString = rowString + "</row>";
tableString = tableString + rowString;
}
} catch (Exception e1) {
e1.printStackTrace(logger);
}
}
}
} catch (Exception e) {
e.printStackTrace(logger);
} finally {
preparedSelect.close();
preparedSelectTarget.close();
selectSourceStmt.close();
checkTarget.close();
rs.close();
}
tableString = tableString + "</table>";
formXmlString(tableString);
if (error == 0) result = "SUCCESS";
return result;
}
你能缩小你的问题吗？有人读完所有代码是不太可能的。 – musiKk 2011-06-07 10:11:38
narrowed down..while可合并方法中的rs.next循环.. – 2011-06-07 10:51:16