org.springframework.jdbc.core.BeanPropertyRowMapper Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.jdbc.core;
import java.beans.PropertyDescriptor;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.NotWritablePropertyException;
import org.springframework.beans.PropertyAccessorFactory;
import org.springframework.beans.TypeMismatchException;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.dao.DataRetrievalFailureException;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
/**
* {@link 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
* meta-data 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, {@code 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 database, 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 {@link RowMapper} implementation.
*
* @author Thomas Risberg
* @author Juergen Hoeller
* @since 2.5
* @param the result type
*/
public class BeanPropertyRowMapper implements RowMapper {
/** Logger available to subclasses. */
protected final Log logger = LogFactory.getLog(getClass());
/** The class we are mapping to. */
@Nullable
private Class mappedClass;
/** Whether we're strictly validating. */
private boolean checkFullyPopulated = false;
/** Whether we're defaulting primitives when mapping a null value. */
private boolean primitivesDefaultedForNullValue = false;
/** ConversionService for binding JDBC values to bean properties. */
@Nullable
private ConversionService conversionService = DefaultConversionService.getSharedInstance();
/** Map of the fields we provide mapping for. */
@Nullable
private Map mappedFields;
/** Set of bean properties we provide mapping for. */
@Nullable
private Set mappedProperties;
/**
* Create a new {@code BeanPropertyRowMapper} for bean-style configuration.
* @see #setMappedClass
* @see #setCheckFullyPopulated
*/
public BeanPropertyRowMapper() {
}
/**
* Create a new {@code BeanPropertyRowMapper}, accepting unpopulated
* properties in the target bean.
* Consider using the {@link #newInstance} factory method instead,
* which allows for specifying the mapped type once only.
* @param mappedClass the class that each row should be mapped to
*/
public BeanPropertyRowMapper(Class mappedClass) {
initialize(mappedClass);
}
/**
* Create a new {@code BeanPropertyRowMapper}.
* @param mappedClass the class that each row should be mapped to
* @param checkFullyPopulated whether we're strictly validating that
* all bean properties have been mapped from corresponding database fields
*/
public BeanPropertyRowMapper(Class mappedClass, boolean checkFullyPopulated) {
initialize(mappedClass);
this.checkFullyPopulated = checkFullyPopulated;
}
/**
* Set the class that each row should be mapped to.
*/
public void setMappedClass(Class mappedClass) {
if (this.mappedClass == null) {
initialize(mappedClass);
}
else {
if (this.mappedClass != mappedClass) {
throw new InvalidDataAccessApiUsageException("The mapped class can not be reassigned to map to " +
mappedClass + " since it is already providing mapping for " + this.mappedClass);
}
}
}
/**
* Get the class that we are mapping to.
*/
@Nullable
public final Class getMappedClass() {
return this.mappedClass;
}
/**
* Set whether we're strictly validating that all bean properties have been mapped
* from corresponding database fields.
* Default is {@code false}, accepting unpopulated properties in the target bean.
*/
public void setCheckFullyPopulated(boolean checkFullyPopulated) {
this.checkFullyPopulated = checkFullyPopulated;
}
/**
* Return whether we're strictly validating that all bean properties have been
* mapped from corresponding database fields.
*/
public boolean isCheckFullyPopulated() {
return this.checkFullyPopulated;
}
/**
* Set whether we're defaulting Java primitives in the case of mapping a null value
* from corresponding database fields.
*
Default is {@code false}, throwing an exception when nulls are mapped to Java primitives.
*/
public void setPrimitivesDefaultedForNullValue(boolean primitivesDefaultedForNullValue) {
this.primitivesDefaultedForNullValue = primitivesDefaultedForNullValue;
}
/**
* Return whether we're defaulting Java primitives in the case of mapping a null value
* from corresponding database fields.
*/
public boolean isPrimitivesDefaultedForNullValue() {
return this.primitivesDefaultedForNullValue;
}
/**
* Set a {@link ConversionService} for binding JDBC values to bean properties,
* or {@code null} for none.
*
Default is a {@link DefaultConversionService}, as of Spring 4.3. This
* provides support for {@code java.time} conversion and other special types.
* @since 4.3
* @see #initBeanWrapper(BeanWrapper)
*/
public void setConversionService(@Nullable ConversionService conversionService) {
this.conversionService = conversionService;
}
/**
* Return a {@link ConversionService} for binding JDBC values to bean properties,
* or {@code null} if none.
* @since 4.3
*/
@Nullable
public ConversionService getConversionService() {
return this.conversionService;
}
/**
* Initialize the mapping meta-data for the given class.
* @param mappedClass the mapped class
*/
protected void initialize(Class mappedClass) {
this.mappedClass = mappedClass;
this.mappedFields = new HashMap<>();
this.mappedProperties = new HashSet<>();
PropertyDescriptor[] pds = BeanUtils.getPropertyDescriptors(mappedClass);
for (PropertyDescriptor pd : pds) {
if (pd.getWriteMethod() != null) {
this.mappedFields.put(lowerCaseName(pd.getName()), pd);
String underscoredName = underscoreName(pd.getName());
if (!lowerCaseName(pd.getName()).equals(underscoredName)) {
this.mappedFields.put(underscoredName, pd);
}
this.mappedProperties.add(pd.getName());
}
}
}
/**
* 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.
* @param name the original name
* @return the converted name
* @since 4.2
* @see #lowerCaseName
*/
protected String underscoreName(String name) {
if (!StringUtils.hasLength(name)) {
return "";
}
StringBuilder result = new StringBuilder();
result.append(lowerCaseName(name.substring(0, 1)));
for (int i = 1; i < name.length(); i++) {
String s = name.substring(i, i + 1);
String slc = lowerCaseName(s);
if (!s.equals(slc)) {
result.append("_").append(slc);
}
else {
result.append(s);
}
}
return result.toString();
}
/**
* Convert the given name to lower case.
* By default, conversions will happen within the US locale.
* @param name the original name
* @return the converted name
* @since 4.2
*/
protected String lowerCaseName(String name) {
return name.toLowerCase(Locale.US);
}
/**
* Extract the values for all columns in the current row.
* Utilizes public setters and result set meta-data.
* @see java.sql.ResultSetMetaData
*/
@Override
public T mapRow(ResultSet rs, int rowNumber) throws SQLException {
Assert.state(this.mappedClass != null, "Mapped class was not specified");
T mappedObject = BeanUtils.instantiateClass(this.mappedClass);
BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(mappedObject);
initBeanWrapper(bw);
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Set populatedProperties = (isCheckFullyPopulated() ? new HashSet<>() : null);
for (int index = 1; index <= columnCount; index++) {
String column = JdbcUtils.lookupColumnName(rsmd, index);
String field = lowerCaseName(StringUtils.delete(column, " "));
PropertyDescriptor pd = (this.mappedFields != null ? this.mappedFields.get(field) : null);
if (pd != null) {
try {
Object value = getColumnValue(rs, index, pd);
if (rowNumber == 0 && logger.isDebugEnabled()) {
logger.debug("Mapping column '" + column + "' to property '" + pd.getName() +
"' of type '" + ClassUtils.getQualifiedName(pd.getPropertyType()) + "'");
}
try {
bw.setPropertyValue(pd.getName(), value);
}
catch (TypeMismatchException ex) {
if (value == null && this.primitivesDefaultedForNullValue) {
if (logger.isDebugEnabled()) {
logger.debug("Intercepted TypeMismatchException for row " + rowNumber +
" and column '" + column + "' with null value when setting property '" +
pd.getName() + "' of type '" +
ClassUtils.getQualifiedName(pd.getPropertyType()) +
"' on object: " + mappedObject, ex);
}
}
else {
throw ex;
}
}
if (populatedProperties != null) {
populatedProperties.add(pd.getName());
}
}
catch (NotWritablePropertyException ex) {
throw new DataRetrievalFailureException(
"Unable to map column '" + column + "' to property '" + pd.getName() + "'", ex);
}
}
else {
// No PropertyDescriptor found
if (rowNumber == 0 && logger.isDebugEnabled()) {
logger.debug("No property found for column '" + column + "' mapped to field '" + field + "'");
}
}
}
if (populatedProperties != null && !populatedProperties.equals(this.mappedProperties)) {
throw new InvalidDataAccessApiUsageException("Given ResultSet does not contain all fields " +
"necessary to populate object of class [" + this.mappedClass.getName() + "]: " +
this.mappedProperties);
}
return mappedObject;
}
/**
* Initialize the given BeanWrapper to be used for row mapping.
* To be called for each row.
* The default implementation applies the configured {@link ConversionService},
* if any. Can be overridden in subclasses.
* @param bw the BeanWrapper to initialize
* @see #getConversionService()
* @see BeanWrapper#setConversionService
*/
protected void initBeanWrapper(BeanWrapper bw) {
ConversionService cs = getConversionService();
if (cs != null) {
bw.setConversionService(cs);
}
}
/**
* Retrieve a JDBC object value for the specified column.
*
The default implementation calls
* {@link JdbcUtils#getResultSetValue(java.sql.ResultSet, int, Class)}.
* Subclasses may override this to check specific value types upfront,
* or to post-process values return from {@code getResultSetValue}.
* @param rs is the ResultSet holding the data
* @param index is the column index
* @param pd the bean property that each result object is expected to match
* @return the Object value
* @throws SQLException in case of extraction failure
* @see org.springframework.jdbc.support.JdbcUtils#getResultSetValue(java.sql.ResultSet, int, Class)
*/
@Nullable
protected Object getColumnValue(ResultSet rs, int index, PropertyDescriptor pd) throws SQLException {
return JdbcUtils.getResultSetValue(rs, index, pd.getPropertyType());
}
/**
* Static factory method to create a new {@code BeanPropertyRowMapper}
* (with the mapped class specified only once).
* @param mappedClass the class that each row should be mapped to
*/
public static BeanPropertyRowMapper newInstance(Class mappedClass) {
return new BeanPropertyRowMapper<>(mappedClass);
}
}