org.springframework.jdbc.core

Class BeanPropertyRowMapper<T>

java.lang.Object

org.springframework.jdbc.core.BeanPropertyRowMapper<T>

All Implemented Interfaces:

RowMapper<T>

Direct Known Subclasses:

ParameterizedBeanPropertyRowMapper

public class BeanPropertyRowMapper<T>
extends java.lang.Object
implements RowMapper<T>

RowMapper implementation that converts a row into a new instance of the specified mapped target class. The mapped target class must be a top-level class and it must have a default or no-arg constructor.

Column values are mapped based on matching the column name as obtained from result set metadata to public setters for the corresponding properties. The names are matched either directly or by transforming a name separating the parts with underscores to the same name using "camel" case.

Mapping is provided for fields in the target class for many common types, e.g.: String, boolean, Boolean, byte, Byte, short, Short, int, Integer, long, Long, float, Float, double, Double, BigDecimal, java.util.Date, etc.

To facilitate mapping between columns and fields that don't have matching names, try using column aliases in the SQL statement like "select fname as first_name from customer".

For 'null' values read from the databasem, we will attempt to call the setter, but in the case of Java primitives, this causes a TypeMismatchException. This class can be configured (using the primitivesDefaultedForNullValue property) to trap this exception and use the primitives default value. Be aware that if you use the values from the generated bean to update the database the primitive value will have been set to the primitive's default value instead of null.

Please note that this class is designed to provide convenience rather than high performance. For best performance consider using a custom RowMapper.

Since:

2.5

Author:

Thomas Risberg, Juergen Hoeller

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	checkFullyPopulated Whether we're strictly validating
protected Log	logger Logger available to subclasses
private java.lang.Class<T>	mappedClass The class we are mapping to
private java.util.Map<java.lang.String,java.beans.PropertyDescriptor>	mappedFields Map of the fields we provide mapping for
private java.util.Set<java.lang.String>	mappedProperties Set of bean properties we provide mapping for
private boolean	primitivesDefaultedForNullValue Whether we're defaulting primitives when mapping a null value

Constructor Summary

Constructors

Constructor and Description
BeanPropertyRowMapper() Create a new BeanPropertyRowMapper for bean-style configuration.
BeanPropertyRowMapper(java.lang.Class<T> mappedClass) Create a new BeanPropertyRowMapper, accepting unpopulated properties in the target bean.
BeanPropertyRowMapper(java.lang.Class<T> mappedClass, boolean checkFullyPopulated) Create a new BeanPropertyRowMapper.

Method Summary

Modifier and Type	Method and Description
protected java.lang.Object	getColumnValue(java.sql.ResultSet rs, int index, java.beans.PropertyDescriptor pd) Retrieve a JDBC object value for the specified column.
java.lang.Class<T>	getMappedClass() Get the class that we are mapping to.
protected void	initBeanWrapper(BeanWrapper bw) Initialize the given BeanWrapper to be used for row mapping.
protected void	initialize(java.lang.Class<T> mappedClass) Initialize the mapping metadata for the given class.
boolean	isCheckFullyPopulated() Return whether we're strictly validating that all bean properties have been mapped from corresponding database fields.
boolean	isPrimitivesDefaultedForNullValue() Return whether we're defaulting Java primitives in the case of mapping a null value from corresponding database fields.
T	mapRow(java.sql.ResultSet rs, int rowNumber) Extract the values for all columns in the current row.
static <T> BeanPropertyRowMapper<T>	newInstance(java.lang.Class<T> mappedClass) Static factory method to create a new BeanPropertyRowMapper (with the mapped class specified only once).
void	setCheckFullyPopulated(boolean checkFullyPopulated) Set whether we're strictly validating that all bean properties have been mapped from corresponding database fields.
void	setMappedClass(java.lang.Class<T> mappedClass) Set the class that each row should be mapped to.
void	setPrimitivesDefaultedForNullValue(boolean primitivesDefaultedForNullValue) Set whether we're defaulting Java primitives in the case of mapping a null value from corresponding database fields.
private java.lang.String	underscoreName(java.lang.String name) Convert a name in camelCase to an underscored name in lower case.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

protected final Log logger

Logger available to subclasses

mappedClass

private java.lang.Class<T> mappedClass

The class we are mapping to

checkFullyPopulated

private boolean checkFullyPopulated

Whether we're strictly validating

primitivesDefaultedForNullValue

private boolean primitivesDefaultedForNullValue

Whether we're defaulting primitives when mapping a null value

mappedFields

private java.util.Map<java.lang.String,java.beans.PropertyDescriptor> mappedFields

Map of the fields we provide mapping for

mappedProperties

private java.util.Set<java.lang.String> mappedProperties

Set of bean properties we provide mapping for

Constructor Detail

BeanPropertyRowMapper

public BeanPropertyRowMapper()

Create a new BeanPropertyRowMapper for bean-style configuration.

See Also:

setMappedClass(java.lang.Class<T>), setCheckFullyPopulated(boolean)

BeanPropertyRowMapper

public BeanPropertyRowMapper(java.lang.Class<T> mappedClass)

Create a new BeanPropertyRowMapper, accepting unpopulated properties in the target bean.

Consider using the newInstance(java.lang.Class<T>) factory method instead, which allows for specifying the mapped type once only.

Parameters:

mappedClass - the class that each row should be mapped to

BeanPropertyRowMapper

public BeanPropertyRowMapper(java.lang.Class<T> mappedClass,
                     boolean checkFullyPopulated)

Create a new BeanPropertyRowMapper.

Parameters:

mappedClass - the class that each row should be mapped to

checkFullyPopulated - whether we're strictly validating that all bean properties have been mapped from corresponding database fields

Method Detail

setMappedClass

public void setMappedClass(java.lang.Class<T> mappedClass)

Set the class that each row should be mapped to.

initialize

protected void initialize(java.lang.Class<T> mappedClass)

Initialize the mapping metadata for the given class.

Parameters:

mappedClass - the mapped class.

underscoreName

private java.lang.String underscoreName(java.lang.String name)

Convert a name in camelCase to an underscored name in lower case. Any upper case letters are converted to lower case with a preceding underscore.

Parameters:

name - the string containing original name

Returns:

the converted name

getMappedClass

public final java.lang.Class<T> getMappedClass()

Get the class that we are mapping to.

setCheckFullyPopulated

public void setCheckFullyPopulated(boolean checkFullyPopulated)

Set whether we're strictly validating that all bean properties have been mapped from corresponding database fields.

Default is false, accepting unpopulated properties in the target bean.

isCheckFullyPopulated

public boolean isCheckFullyPopulated()

Return whether we're strictly validating that all bean properties have been mapped from corresponding database fields.

setPrimitivesDefaultedForNullValue

public void setPrimitivesDefaultedForNullValue(boolean primitivesDefaultedForNullValue)

Set whether we're defaulting Java primitives in the case of mapping a null value from corresponding database fields.

Default is false, throwing an exception when nulls are mapped to Java primitives.

isPrimitivesDefaultedForNullValue

public boolean isPrimitivesDefaultedForNullValue()

Return whether we're defaulting Java primitives in the case of mapping a null value from corresponding database fields.

mapRow

public T mapRow(java.sql.ResultSet rs,
       int rowNumber)
         throws java.sql.SQLException

Extract the values for all columns in the current row.

Utilizes public setters and result set metadata.

Specified by:

mapRow in interface RowMapper<T>

Parameters:

rs - the ResultSet to map (pre-initialized for the current row)

rowNumber - the number of the current row

Returns:

the result object for the current row

Throws:

java.sql.SQLException - if a SQLException is encountered getting column values (that is, there's no need to catch SQLException)

See Also:

ResultSetMetaData

initBeanWrapper

protected void initBeanWrapper(BeanWrapper bw)

Initialize the given BeanWrapper to be used for row mapping. To be called for each row.

The default implementation is empty. Can be overridden in subclasses.

Parameters:

bw - the BeanWrapper to initialize

getColumnValue

protected java.lang.Object getColumnValue(java.sql.ResultSet rs,
                              int index,
                              java.beans.PropertyDescriptor pd)
                                   throws java.sql.SQLException

Retrieve a JDBC object value for the specified column.

The default implementation calls JdbcUtils.getResultSetValue(java.sql.ResultSet, int, Class). Subclasses may override this to check specific value types upfront, or to post-process values return from getResultSetValue.

Parameters:

rs - is the ResultSet holding the data

index - is the column index

pd - the bean property that each result object is expected to match (or null if none specified)

Returns:

the Object value

Throws:

java.sql.SQLException - in case of extraction failure

See Also:

JdbcUtils.getResultSetValue(java.sql.ResultSet, int, Class)

newInstance

public static <T> BeanPropertyRowMapper<T> newInstance(java.lang.Class<T> mappedClass)

Static factory method to create a new BeanPropertyRowMapper (with the mapped class specified only once).

Parameters:

mappedClass - the class that each row should be mapped to