Class KeyedHandler<K>
java.lang.Object
org.apache.commons.dbutils.handlers.AbstractKeyedHandler<K,Map<String,Object>>
org.apache.commons.dbutils.handlers.KeyedHandler<K>
- Type Parameters:
K- The type of the key
- All Implemented Interfaces:
ResultSetHandler<Map<K,Map<String, Object>>>
ResultSetHandler implementation that returns a Map of Maps.
ResultSet rows are converted into Maps which are then stored
in a Map under the given key.
If you had a Person table with a primary key column called ID, you could retrieve rows from the table like this:
ResultSetHandler h = new KeyedHandler("id");
Map found = (Map) queryRunner.query("select id, name, age from person", h);
Map jane = (Map) found.get(new Long(1)); // jane's id is 1
String janesName = (String) jane.get("name");
Integer janesAge = (Integer) jane.get("age");
Note that the "id" passed to KeyedHandler and "name" and "age" passed to the
returned Map's get() method can be in any case. The data types returned for
name and age are dependent upon how your JDBC driver converts SQL column
types from the Person table into Java types.
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This class is thread safe.
- Since:
- 1.1
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected final intThe column index to retrieve key values from.protected final StringThe column name to retrieve key values from.protected final RowProcessorThe RowProcessor implementation to use when converting rows into Objects. -
Constructor Summary
ConstructorsConstructorDescriptionCreates a new instance of KeyedHandler.KeyedHandler(int columnIndex) Creates a new instance of KeyedHandler.KeyedHandler(String columnName) Creates a new instance of KeyedHandler.KeyedHandler(RowProcessor convert) Creates a new instance of KeyedHandler. -
Method Summary
Modifier and TypeMethodDescriptionprotected KThis factory method is called byhandle()to retrieve the key value from the currentResultSetrow.This factory method is called byhandle()to store the currentResultSetrow in some object.Methods inherited from class org.apache.commons.dbutils.handlers.AbstractKeyedHandler
createMap, handle
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Field Details
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convert
The RowProcessor implementation to use when converting rows into Objects. -
columnIndex
The column index to retrieve key values from. Defaults to 1. -
columnName
The column name to retrieve key values from. Either columnName or columnIndex will be used but never both.
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Constructor Details
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KeyedHandler
public KeyedHandler()Creates a new instance of KeyedHandler. The value of the first column of each row will be a key in the Map. -
KeyedHandler
Creates a new instance of KeyedHandler.- Parameters:
columnIndex- The values to use as keys in the Map are retrieved from the column at this index.
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KeyedHandler
Creates a new instance of KeyedHandler. The value of the first column of each row will be a key in the Map.- Parameters:
convert- TheRowProcessorimplementation to use when converting rows into Maps
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KeyedHandler
Creates a new instance of KeyedHandler.- Parameters:
columnName- The values to use as keys in the Map are retrieved from the column with this name.
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Method Details
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createKey
This factory method is called byhandle()to retrieve the key value from the currentResultSetrow. This implementation returnsResultSet.getObject()for the configured key column name or index.- Specified by:
createKeyin classAbstractKeyedHandler<K,Map<String, Object>> - Parameters:
rs- ResultSet to create a key from- Returns:
- Object from the configured key column name/index
- Throws:
SQLException- if a database access error occursClassCastException- if the class datatype does not match the column type
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createRow
This factory method is called byhandle()to store the currentResultSetrow in some object. This implementation returns aMapwith case insensitive column names as keys. Calls tomap.get("COL")andmap.get("col")return the same value.- Specified by:
createRowin classAbstractKeyedHandler<K,Map<String, Object>> - Parameters:
resultSet- ResultSet to create a row from- Returns:
- Object typed Map containing column names to values
- Throws:
SQLException- if a database access error occurs
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