JdbcTemplate multiple result sets
I am trying to find an easy way to deal with Stored Procedures / SQL returning multiple result sets. I have been using the SimpleJdbcOperations#queryForList()
method however this will only return the first result set as a List<Map<String, Object>>
. I need to be able to get multiple result sets, ideally as a Collection
of List<Map<String, Object>>
or something. The program I am writing is a middleware component so I don't know what the SQL will be, or the form of the result set.
I think I have to use the JdbcOperations
class which gives me access to more methods, including execute(CallableStatementCreator csc, CallableStatementCallback<T> action)
but now I am stuck.
CallableStatementCallback<T> callback = new CallableStatementCallback<T>() {
@Override
public T doInCallableStatement(CallableStatement cs) throws SQLException, DataAccessException
{
boolean results = cs.execute(request);
while(results)
{
ResultSet result = cs.getResultSet();
results = cs.getMoreResults();
}
return null;
}
};
I am not really sure how to use the method though, or what to do with the ResultSet
to get my generic List<Map<String, Object>>
s.
I managed to get a Set<ResultSet>
using this code,
private Set<ResultSet> executeProcedure(final String sql)
{
return jdbc.execute(new CallableStatementCreator() {
@Override
public CallableStatement createCallableStatement(Connection con) throws SQLException
{
return con.prepareCall(sql);
}
}, new CallableStatementCallback<Set<ResultSet>>() {
@Override
public Set<ResultSet> doInCallableStatement(CallableStatement cs) throws SQLException
{
Set<ResultSet> results = new HashSet<>();
boolean resultsAvailable = cs.execute();
while (resultsAvailable)
{
results.add(cs.getResultSet());
resultsAvailable = cs.getMoreResults();
}
return results;
}
});
}
Just going to look at translating a ResultSet
into List<Map<String, Object>>
.
You can use the resultSet.getMetaData() method to work out what columns are in the data:
ResultSetMetaData meta = resultSet.getMetaData();
int colcount = meta.getColumnCount();
for (int i = 1; i <= colcount; i++)
{
String name = meta.getColumnLabel(i); // This is the name of the column
int type = meta.getColumnType(i); // from java.sql.Types
// Maybe add to a Map,List, etc...
}
You can then do as the other commentors have mentioned do a loop through the ResultSet pulling out the data you need:
while (resultSet.hasNext())
{
resultSet.next();
// Find the columns you want to extract (via the above method maybe) and add to your row.
}
我使用下面的方法以List<Map<String, Object>>
形式获取ResultSet的List<Map<String, Object>>
public List<List<Map<String, Object>>> executeProcedure(final String sql) {
return jdbcTemplate.execute(new CallableStatementCreator() {
@Override
public CallableStatement createCallableStatement(Connection con) throws SQLException {
return con.prepareCall(sql);
}
}, new CallableStatementCallback<List<List<Map<String, Object>>>>() {
@Override
public List<List<Map<String, Object>>> doInCallableStatement(CallableStatement cs) throws SQLException {
boolean resultsAvailable = cs.execute();
List<List<Map<String, Object>>> list = new ArrayList<List<Map<String, Object>>>();
while (resultsAvailable) {
ResultSet resultSet = cs.getResultSet();
List<Map<String, Object>> subList = new ArrayList<Map<String, Object>>();
while (resultSet.next()) {
ResultSetMetaData meta = resultSet.getMetaData();
int colcount = meta.getColumnCount();
Map<String, Object> map = new HashMap<String, Object>();
for (int i = 1; i <= colcount; i++) {
String name = meta.getColumnLabel(i);
map.put(name, resultSet.getString(i));
}
subList.add(map);
}
list.add(subList);
resultsAvailable = cs.getMoreResults();
}
return list;
}
});
}
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