CODEWITHSUNDEEP
javadatabaseresultset
James MV
James MV

Reputation: 8717

Put ResultSet into HashMap?

I have an mySQL ResultSet and I want to store that in my HashMap:

Map<String, Integer> myMap = new HashMap<String, Integer>();

Gets the Result set here then:

while(rs.next()){                           
    rs.put("Column1","Column2");
}

This is not right, could some explain the correct way to do it please?

Upvotes: 4

Views: 36888

Answers (3)

user3766614
user3766614

Reputation: 191

 List<Map<String, String>> list = new ArrayList<Map<String, String>>();
        ResultSetMetaData meta = rs.getMetaData();
        while (rs.next()) {
            Map map = new HashMap();
            for (int i = 1; i <= meta.getColumnCount(); i++) {
                String key = meta.getColumnName(i);
                String value = rs.getString(key);
                map.put(key, value);
            }
            list.add(map);
        }

Upvotes: 19

Gray
Gray

Reputation: 116828

If I read your question correctly, it would be something like:

Map<String, Integer> myMap = new HashMap<String, Integer>();
...
// parsing the column each time is a linear search
int column1Pos = rs.findColumn("Column1");
int column2Pos = rs.findColumn("Column2");
while (rs.next()) {
    String column1 = rs.getString(column1Pos);
    int column2 = rs.getInt(column2Pos);
    myMap.put(column1, column2);
}

Upvotes: 2

digitaljoel
digitaljoel

Reputation: 26574

You probably want a Map<YourKeyType, Map<String, Integer>>.

So you are mapping each row by id (whatever type that is) to a map of column/value. Here I assumed every column was Integer since that's what you had in your question, but you could use Object if they differ. Then you could access the values with myMap.get(myId).get( "column1" ); or walk it using the keySet() or whatever you need to do with it.

To populate the map, you would do something like

Map<KeyType, Map<String, Object>> resultMap = new HashMap<KeyType, Map<String, Object>>();
while( rs.next()) {
    Map<String, Object> tmpMap = new HashMap<String, Object>();
    tmpMap.put( "Column1", rs.get( "Column1" );
    // etc. for other columns
    resultMap.put( rs.get( "id" ), tmpMap );
}

Upvotes: 0

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