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How to define array of objects in a properties file and read from Java program

I have a properties file like this.
property[0].name=A
property[0].value=1
property[1].name=B
property[1].value=2
property[2].name=C
property[2].value=3
How to read this file as a list of objects of a class {name, value} in plain java program using ResourceBundle or Properties?
Here is the class.
public class XYZ {
private String name;
private String value;
// Getters & Setters
}
I need to get like this.
ArrayList<XYZ> propertiesList = SomeUtility.getProperties("property", XYZ.class);
Utility class might be like this.
public class SomeUtility {
public static ArrayList getProperties(String key, Class cls) {
//logic
}
}

I might not understand exactly what you want so feel free to correct me and give me more constraints to work with but here is a simple way to read a Properties file located somewhere in your project:
private static void readPropertiesFile(String path) throws IOException {
java.util.Map<String, String> map = new java.util.LinkedHashMap<>();
Properties properties = new Properties();
InputStream inputStream = new FileInputStream(path);
properties.load(inputStream);
for (String name : properties.stringPropertyNames()) {
map.put(name, properties.getProperty(name));
}
for (java.util.Map.Entry<String, String> entry : map.entrySet()) {
System.out.printf("Property Key: %s, Property Value: %s%n", entry.getKey(), entry.getValue());
}
}
Output
Property Key: property[0].name, Property Value: A
Property Key: property[1].name, Property Value: B
Property Key: property[0].value, Property Value: 1
Property Key: property[1].value, Property Value: 2
Property Key: property[2].name, Property Value: C
Property Key: property[2].value, Property Value: 3

This is the solution I wrote, but it involves Reflect and Gson. Is there any better way to do this? Anything already available which is fine tuned like Apache's.
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.lang.reflect.Field;
import java.util.*;
public class ListResourceBundle {
public static final Gson gson = new Gson();
private final ResourceBundle bundle;
public ListResourceBundle(ResourceBundle bundle) {
this.bundle = bundle;
}
public List<?> getProperties(String key, Class<?> cls) {
final int maxArraySize = getMaxArraySize(key, getMatchingKeys(key));
final List<String> fields = getFields(cls);
final List<Object> result = new ArrayList<>();
for (int i = 0; i < maxArraySize; i++) {
JsonObject jsonObject = new JsonObject();
for (String field : fields) {
jsonObject.addProperty(field, getStringOrNull(key + "[" + i + "]." + field));
}
result.add(gson.fromJson(jsonObject, cls));
}
System.out.println("result.toString() = " + result.toString());
return result;
}
public List<String> getMatchingKeys(String key) {
Enumeration<String> keys = bundle.getKeys();
List<String> matchingKeys = new ArrayList<>();
while(keys.hasMoreElements()) {
String k = keys.nextElement();
if(k.startsWith(key)) {
matchingKeys.add(k);
}
}
Collections.sort(matchingKeys);
return matchingKeys;
}
public int getMaxArraySize(String key, List<String> matchingKeys) {
int maxArraySize = 0;
for (int i = 0; ; i++) {
boolean indexAvailable = false;
for (String matchingKey : matchingKeys) {
if(matchingKey.startsWith(key + "[" + i + "]")) {
indexAvailable = true;
break;
}
}
if(indexAvailable) {
maxArraySize++;
} else {
break;
}
}
return maxArraySize;
}
public String getStringOrNull(String key) {
try {
return bundle.getString(key);
} catch (MissingResourceException e) {
return null;
}
}
public List<String> getFields(Class<?> cls) {
final List<String> fields = new ArrayList<>();
for (Field field : cls.getDeclaredFields()) {
fields.add(field.getName());
}
return fields;
}
public static void main(String[] args) {
ResourceBundle bundle = ResourceBundle.getBundle("com.example.application.resources.Resource");
ListResourceBundle applicationResourceBundle = new ListResourceBundle(bundle);
applicationResourceBundle.getProperties("property", ReportParam.class);
}
}
Resource:
property[0].name=A
property[0].value=1
property[1].name=B
property[1].value=2
property[2].name=C
property[2].value=3
Output:
result.toString() = [
ReportParam{name='A', value='1'},
ReportParam{name='B', value='2'},
ReportParam{name='C', value='3'}]
Process finished with exit code 0

I know it's bit late of an answer, but if I understand your problem statement correctly, you can use :
#ConfigurationProperties
to get your job done.
Here is my spring-boot example with a YAML file for the sake of convenience (same can be achieved through properties file as well).
application.yaml:
xyz:
xyzprops :
-
name: cbc
value: 441
-
name: obc
value: 443
XYZ class:
#Component
#ConfigurationProperties(prefix = "xyz")
public class XYZ{
private List<XYZProps> xyzprops;
public List<XYZProps> getXyzprops() {
return xyzprops;
}
public void setXyzprops(List<XYZProps> xyzprops) {
this.xyzprops = xyzprops;
}
public class XYZProps{
String name;
String value;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
}
And then #Autowire XYZ where you want to use it.

I would use JSON:
in your file:
property=[{"name":"A","value":"1"},{"name":"B","value":"2"},{"name":"C","value":"3"}]
and then deserialize it using com.google.gson.gson (or any other) library:
ArrayList<XYZ> propertiesList;
propertiesList = new gsonbuilder().create().fromjson(property, propertiesList.class);
NOTE: I haven't tested this code, and i'm not very familiar with java so i am sure there is a better,cleaner way to implement this.

Read JSON Nested element using reflection without using JsonFactory or ObjectMapper

[Unable to access property of another object stored in Arraylist]
I am creating an function to get JSON input in object from RESTful Web service input and format it again in JSON format to call other web service.
I have limitation that I can not use any JSON API for object mapping hence using Java reflection core API.
I am able to create JSON format from Input for simple elements but unable to access nested elements (another user defined POJO class ). I am using arraylist.
Input
{
"GenesisIncidents": {
"service": "Transmission",
"affectedCI": "22BT_ORNC03",
"opt_additionalAffectedItems": [
{
"itemType": "NODE-ID",
"ItemName": "22BT_ORNC03"
},
{
"ItemType": "CCT",
"ItemName": "A_circuit_id"
}]
}
}
GenesisIncidents.class
import java.util.ArrayList;
import java.util.Date;
public class GenesisIncidents {
private String service;
private String affectedCI;
private ArrayList<AdditionalAffectedItems> opt_additionalAffectedItems;
public GenesisIncidents(){}
public String getService() {
return service;
}
public void setService(String service) {
this.service = service;
}
public String getAffectedCI() {
return affectedCI;
}
public void setAffectedCI(String affectedCI) {
this.affectedCI = affectedCI;
}
public ArrayList<AdditionalAffectedItems> getOpt_additionalAffectedItems() {
return opt_additionalAffectedItems;
}
public void setOpt_additionalAffectedItems(ArrayList<AdditionalAffectedItems> opt_additionalAffectedItems) {
this.opt_additionalAffectedItems = opt_additionalAffectedItems;
}
}
AdditionalAffectedItems.class
public class AdditionalAffectedItems {
private String itemType;
private String itemName;
public AdditionalAffectedItems(){
super();
}
public String getItemType() {
return itemType;
}
public void setItemType(String itemType) {
this.itemType = itemType;
}
public String getItemName() {
return itemName;
}
public void setItemName(String itemName) {
this.itemName = itemName;
}
}
Implemetation
public void updateTicketExt(GenesisIncidents genesisIncidents) {
try{
Field allFields[]=genesisIncidents.getClass().getDeclaredFields();
Method allMethods[] = genesisIncidents.getClass().getDeclaredMethods();
String jsonString ="{\r\n \""+genesisIncidents.getClass().getName().toString().substring(48)+"\": {";
final String preStr="\r\n \""; //To create a JSON object format.
final String postStr="\": "; //To create a JSON object format.
int totalNoOfFields=allFields.length;
for (Field field : allFields) {
System.out.println(field.getType());
String getter="get"+StringUtils.capitalize(field.getName());
Method method= genesisIncidents.getClass().getMethod(getter, null);
try{
if(field.getType().toString().contains("Integer"))
jsonString=jsonString + preStr + field.getName() + postStr +method.invoke(genesisIncidents).toString()+",";
else
jsonString=jsonString + preStr + field.getName() + postStr +"\""+method.invoke(genesisIncidents).toString()+"\",";
if(field.getType().toString().contains("ArrayList")){
System.out.println("ArrayListElement found");
genesisIncidents.getOpt_additionalAffectedItems().forEach(obj->{System.out.println(obj.getItemName());});
//convertArrayToJSON(field, genesisIncidents);
}
}catch(NullPointerException npe)
{
System.out.println("Null value in field.");
continue;
}
}
jsonString=jsonString.substring(0,jsonString.length()-1);
jsonString=jsonString+"\r\n }\r\n }";
System.out.println("\n"+jsonString);
}catch(Exception jex){
jex.printStackTrace();
}
}
My below code line is unable to access object stored under array list.
genesisIncidents.getOpt_additionalAffectedItems().forEach(obj->{System.out.println(obj.getItemName());});
OUTPUT
karaf#root>class java.lang.String
class java.lang.String
class java.lang.String
class java.util.ArrayList
ArrayListElement found
null
null
{
"GenesisIncidents": {
"service": "Transmission",
"affectedCI": "22BT_ORNC03",
"opt_additionalAffectedItems": " [org.apache.servicemix.examples.camel.rest.model.AdditionalAffectedItems#5881a 895, org.apache.servicemix.examples.camel.rest.model.AdditionalAffectedItems#399b4e eb]"
}
}

I have fiddled around with your example I have managed to get it working. This will produce the correct JSON string by passing in an instance of a GenesisIncident object. I guess that there is much room for improvement here but this can serve as an example.
public static String genesisToJson(GenesisIncidents incidents) {
try{
StringBuilder jsonBuilder = new StringBuilder();
jsonBuilder.append("{\r\n \"")
.append(incidents.getClass().getSimpleName())
.append("\": {");
Field allFields[] = incidents.getClass().getDeclaredFields();
for (Field field : allFields) {
String getter = getGetterMethod(field);
Method method = incidents.getClass().getMethod(getter, null);
try{
if(field.getType().isAssignableFrom(Integer.class)) {
jsonBuilder.append(preStr).append(field.getName()).append(postStr)
.append(method.invoke(incidents).toString()).append(",");
} else if (field.getType().isAssignableFrom(String.class)) {
jsonBuilder.append(preStr).append(field.getName()).append(postStr).append("\"")
.append(method.invoke(incidents).toString()).append("\",");
} else if (field.getType().isAssignableFrom(List.class)) {
System.out.println("ArrayListElement found");
getInnerObjectToJson(field, incidents.getOptItems(), jsonBuilder);
}
} catch(NullPointerException npe) {
System.out.println("Null value in field.");
continue;
}
}
jsonBuilder.append("\r\n } \r\n }");
return jsonBuilder.toString();
}catch(Exception jex){
jex.printStackTrace();
}
return null;
}
private static void getInnerObjectToJson(Field field, List<AdditionalAffectedItems> items, StringBuilder builder)
throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
builder.append(preStr).append(field.getName()).append(postStr).append("[");
for (var item : items) {
var fields = List.of(item.getClass().getDeclaredFields());
builder.append("{");
for (var f : fields) {
String getter = getGetterMethod(f);
Method method = item.getClass().getMethod(getter, null);
builder.append(preStr).append(f.getName()).append(postStr).append("\"")
.append(method.invoke(item).toString()).append("\"");
if (!(fields.indexOf(f) == (fields.size() - 1))) {
builder.append(",");
}
}
if (items.indexOf(item) == (items.size() - 1)) {
builder.append("}\r\n");
} else {
builder.append("},\r\n");
}
}
builder.append("]");
}
private static String getGetterMethod(Field field) {
return "get" + StringUtils.capitalize(field.getName());
}

How can I use BeanUtils converter to List?

Here, the request Param string is :
firstName=jack&lastName=lily&gender=1&foods=Steak&foods=Pizza&quote=Enter+your+favorite+quote!&education=Jr.High&tOfD=Day
And Mapped class is :
public class Student {
private String firstName;
private String lastName;
private Integer gender;
private List<String> foods;
private String quote;
private String education;
private String tOfD;
getXxx()....;
setXxx()....;
}
And Now, I want to write a generic util class to convert the string to a bean.
public final class InjectUtil<T> {
private static final Logger LOGGER = LoggerFactory.getLogger(InjectUtil.class);
public static <T> T converter2Obj(String source, Class<T> tClass) {
T t = null;
try {
t = tClass.newInstance();
if(source != null && source.length() > 0) {
String[] fields = source.split("&");
for(String field : fields) {
String[] fieldKeyValue = field.split("\\=");
String fieldKey = fieldKeyValue[0];
String fieldValue = fieldKeyValue[1];
// help
}
}
} catch(InstantiationException | IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
return t;
}
}
take care of the help, how can i use BeanUtils converter the "foods=Steak&foods=Pizza" to the List attribute.

Here is a way of doing it :
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.beanutils.BeanUtils;
public final class InjectUtil<T> {
// private static final Logger LOGGER =
// LoggerFactory.getLogger(InjectUtil.class);
public static <T> T converter2Obj(String source, Class<T> tClass) {
T t = null;
try {
t = tClass.newInstance();
Map<String, Object> params = new HashMap<String, Object>();
if (source != null && source.length() > 0) {
String[] fields = source.split("&");
for (String field : fields) {
String[] fieldKeyValue = field.split("\\=");
String fieldKey = fieldKeyValue[0];
String fieldValue = fieldKeyValue[1];
if (params.containsKey(fieldKey)) {
//the key does not exist as yet
Object keyValueRetrieved = params.get(fieldKey);
if (keyValueRetrieved instanceof String) {
//key exists , it is single value that has been added now.
//change that now to a list to add more values
ArrayList<String> values = new ArrayList<String>();
values.add(keyValueRetrieved.toString());
values.add(fieldValue);
params.put(fieldKey, values);
} else {
//key exists , it is a list already. Add more values
((ArrayList<String>) keyValueRetrieved).add(fieldValue);
}
} else {
params.put(fieldKey, fieldValue);
}
}
}
BeanUtils.populate(t, params);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("--------------------------------------------");
System.out.println(t.toString());
System.out.println("--------------------------------------------");
return t;
}
}
There are optimizations you can do , hopefully this gives you an idea

You can use as follows, you need to populate foodList (with values as [Steak,Pizza]) and then set to the bean using following method.
PropertyUtils.setProperty(studentBean, "foods", foodList);
or
BeanUtils.setProperty(studentBean, "foods", foodList);

Hibernate gives a strange ClassCast exception (using Transformers)

This code:
#Override
public List<FactCodeDto> getAllFactsWithoutParentsAsFactDto() {
String completeQuery = FactCodeQueries.SELECT_DTO_FROM_FACT_WITH_NO_PARENTS;
Query query = createHibernateQueryForUnmappedTypeFactDto(completeQuery);
List<FactCodeDto> factDtoList = query.list(); //line 133
return factDtoList;
}
calling this method:
private Query createHibernateQueryForUnmappedTypeFactDto(String sqlQuery) throws HibernateException {
return FactCodeQueries.addScalars(createSQLQuery(sqlQuery)).setResultTransformer(Transformers.aliasToBean(FactCodeDto.class));
}
gives me a ClassCastException -> part of the trace:
Caused by: java.lang.ClassCastException: org.bamboomy.cjr.dto.FactCodeDto cannot be cast to java.util.Map
at org.hibernate.property.access.internal.PropertyAccessMapImpl$SetterImpl.set(PropertyAccessMapImpl.java:102)
at org.hibernate.transform.AliasToBeanResultTransformer.transformTuple(AliasToBeanResultTransformer.java:78)
at org.hibernate.hql.internal.HolderInstantiator.instantiate(HolderInstantiator.java:75)
at org.hibernate.loader.custom.CustomLoader.getResultList(CustomLoader.java:435)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2423)
at org.hibernate.loader.Loader.list(Loader.java:2418)
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:336)
at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:1898)
at org.hibernate.internal.AbstractSessionImpl.list(AbstractSessionImpl.java:318)
at org.hibernate.internal.SQLQueryImpl.list(SQLQueryImpl.java:125)
at org.bamboomy.cjr.dao.factcode.FactCodeDAOImpl.getAllFactsWithoutParentsAsFactDto(FactCodeDAOImpl.java:133)
Which is pretty strange because, indeed, if you look up the source code of Hibernate it tries to do this:
#Override
#SuppressWarnings("unchecked")
public void set(Object target, Object value, SessionFactoryImplementor factory) {
( (Map) target ).put( propertyName, value ); //line 102
}
Which doesn't make any sense...
target is of type Class and this code tries to cast it to Map,
why does it try to do that???
any pointers are more than welcome...
I'm using Hibernate 5 (and am upgrading from 3)...
edit: I also use Spring (4.2.1.RELEASE; also upgrading) which calls these methods upon deploy, any debugging pointers are most welcome as well...
edit 2: (the whole FactCodeDto class, as requested)
package org.bamboomy.cjr.dto;
import org.bamboomy.cjr.model.FactCode;
import org.bamboomy.cjr.model.FactCodeType;
import org.bamboomy.cjr.utility.FullDateUtil;
import org.bamboomy.cjr.utility.Locales;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.springframework.util.Assert;
import java.util.*;
#Getter
#Setter
#ToString
public class FactCodeDto extends TreeNodeValue {
private String cdFact;
private String cdFactSuffix;
private Boolean isSupplementCode;
private Boolean isTitleCode;
private Boolean mustBeFollowed;
private Date activeFrom;
private Date activeTo;
private Boolean isCode;
private Long idFact;
private Long idParent;
private String type;
Map<Locale, String> description = new HashMap<Locale, String>(3);
public FactCodeDto() {
}
public FactCodeDto(String prefix, String suffix) {
super();
this.cdFact = prefix;
this.cdFactSuffix = suffix;
}
public FactCodeDto(String cdFact, String cdFactSuffix, Boolean isSupplementCode, Boolean mustBeFollowed) {
super();
this.cdFact = cdFact;
this.cdFactSuffix = cdFactSuffix;
this.isSupplementCode = isSupplementCode;
this.mustBeFollowed = mustBeFollowed;
}
public FactCodeDto(String cdFact, String cdFactSuffix, Boolean isSupplementCode, Boolean mustBeFollowed, Long idFact, Long idParent, Boolean isCode, Boolean isTitleCode, Date from, Date to, Map<Locale, String> descriptions,String type) {
super();
this.cdFact = cdFact;
this.cdFactSuffix = cdFactSuffix;
this.isSupplementCode = isSupplementCode;
this.mustBeFollowed = mustBeFollowed;
this.idFact = idFact;
this.idParent = idParent;
this.isCode = isCode;
this.isTitleCode = isTitleCode;
this.activeFrom = from;
this.activeTo = to;
if (descriptions != null) {
this.description = descriptions;
}
this.type = type;
}
public FactCodeDto(FactCode fc) {
this(fc.getPrefix(), fc.getSuffix(), fc.isSupplementCode(), fc.isHasMandatorySupplCodes(), fc.getId(), fc.getParent(), fc.isActualCode(), fc.isTitleCode(), fc.getActiveFrom(), fc.getActiveTo(), fc.getAllDesc(),fc.getType().getCode());
}
public String formatCode() {
return FactCode.formatCode(cdFact, cdFactSuffix);
}
public boolean isActive() {
Date now = new Date(System.currentTimeMillis());
return FullDateUtil.isBetweenDates(now, this.activeFrom, this.activeTo);
}
public void setDescFr(String s) {
description.put(Locales.FRENCH, s);
}
public void setDescNl(String s) {
description.put(Locales.DUTCH, s);
}
public void setDescDe(String s) {
description.put(Locales.GERMAN, s);
}
/**
* public String toString() {
* StringBuilder sb = new StringBuilder();
* sb.append(getIdFact() + ": ")
* .append(getIdParent() + ": ")
* .append(" " + cdFact + cdFactSuffix + ": " + (isSupplementCode ? "NO Principal " : " Principal "))
* .append((mustBeFollowed ? " Must Be Followed " : "NOT Must Be Followed "));
* return sb.toString();
* }
*/
public Map<Locale, String> getDescription() {
return description;
}
#Override
public int hashCode() {
final int prime = 31;
int result = 1;
String fullCode = formatCode();
result = prime * result + ((fullCode == null) ? 0 : fullCode.hashCode());
return result;
}
#Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
FactCodeDto other = (FactCodeDto) obj;
return formatCode().equals(other.formatCode());
}
#Override
public boolean isChildOf(TreeNodeValue value) {
Assert.notNull(value);
boolean isChild = false;
if (value instanceof FactCodeDto) {
if (this.getIdParent() != null) {
isChild = this.getIdParent().equals(((FactCodeDto) value).getIdFact());
}
}
return isChild;
}
#Override
public boolean isBrotherOf(TreeNodeValue value) {
Assert.notNull(value);
boolean isBrother = false;
if (value instanceof FactCodeDto) {
if (this.getIdParent() != null) {
isBrother = this.getIdParent().equals(((FactCodeDto) value).getIdParent());
}
}
return isBrother;
}
#Override
public boolean isParentOf(TreeNodeValue value) {
Assert.notNull(value);
boolean isParent = false;
if (value instanceof FactCodeDto) {
isParent = this.getIdFact().equals(((FactCodeDto) value).getIdParent());
}
return isParent;
}
#Override
public int compareTo(TreeNodeValue to) {
if (to instanceof FactCodeDto) {
return formatCode().compareTo(((FactCodeDto) to).formatCode());
} else return 1;
}
public String getCode() {
return formatCode();
}
}

I found that AliasToBean has changed in Hibernate 5. For me adding getter for my field fixed the problem.

This exception occurs when the setters and getters are not mapped correctly to the column names.
Make sure you have the correct getters and setters for the query(Correct names and correct datatypes).
Read more about it here:
http://javahonk.com/java-lang-classcastexception-com-wfs-otc-datamodels-imagineexpirymodel-cannot-cast-java-util-map/

I do some investigation on this question. The problem is that Hibernate converts aliases for column names to upper case — cdFact becomesCDFACT.
Read for a more deeply explanation and workaround here:
mapping Hibernate query results to custom class?

In the end it wasn't so hard to find a solution,
I just created my own (custom) ResultTransformer and specified that in the setResultTransformer method:
private Query createHibernateQueryForUnmappedTypeFactDto(String sqlQuery) throws HibernateException {
return FactCodeQueries.addScalars(createSQLQuery(sqlQuery)).setResultTransformer(new FactCodeDtoResultTransformer());
//return FactCodeQueries.addScalars(createSQLQuery(sqlQuery)).setResultTransformer(Transformers.aliasToBean(FactCodeDto.class));
}
the code of the custom result transformer:
package org.bamboomy.cjr.dao.factcode;
import org.bamboomy.cjr.dto.FactCodeDto;
import java.util.Date;
import java.util.List;
/**
* Created by a162299 on 3-11-2015.
*/
public class FactCodeDtoResultTransformer implements org.hibernate.transform.ResultTransformer {
#Override
public Object transformTuple(Object[] objects, String[] strings) {
FactCodeDto result = new FactCodeDto();
for (int i = 0; i < objects.length; i++) {
setField(result, strings[i], objects[i]);
}
return result;
}
private void setField(FactCodeDto result, String string, Object object) {
if (string.equalsIgnoreCase("cdFact")) {
result.setCdFact((String) object);
} else if (string.equalsIgnoreCase("cdFactSuffix")) {
result.setCdFactSuffix((String) object);
} else if (string.equalsIgnoreCase("isSupplementCode")) {
result.setIsSupplementCode((Boolean) object);
} else if (string.equalsIgnoreCase("isTitleCode")) {
result.setIsTitleCode((Boolean) object);
} else if (string.equalsIgnoreCase("mustBeFollowed")) {
result.setMustBeFollowed((Boolean) object);
} else if (string.equalsIgnoreCase("activeFrom")) {
result.setActiveFrom((Date) object);
} else if (string.equalsIgnoreCase("activeTo")) {
result.setActiveTo((Date) object);
} else if (string.equalsIgnoreCase("descFr")) {
result.setDescFr((String) object);
} else if (string.equalsIgnoreCase("descNl")) {
result.setDescNl((String) object);
} else if (string.equalsIgnoreCase("descDe")) {
result.setDescDe((String) object);
} else if (string.equalsIgnoreCase("type")) {
result.setType((String) object);
} else if (string.equalsIgnoreCase("idFact")) {
result.setIdFact((Long) object);
} else if (string.equalsIgnoreCase("idParent")) {
result.setIdParent((Long) object);
} else if (string.equalsIgnoreCase("isCode")) {
result.setIsCode((Boolean) object);
} else {
throw new RuntimeException("unknown field");
}
}
#Override
public List transformList(List list) {
return list;
}
}
in hibernate 3 you could set Aliasses to queries but you can't do that anymore in hibernate 5 (correct me if I'm wrong) hence the aliasToBean is something you only can use when actually using aliasses; which I didn't, hence the exception.

Im my case :
=> write sql query and try to map result to Class List
=> Use "Transformers.aliasToBean"
=> get Error "cannot be cast to java.util.Map"
Solution :
=> just put \" before and after query aliases
ex:
"select first_name as \"firstName\" from test"
The problem is that Hibernate converts aliases for column names to upper case or lower case

I solved it by defining my own custom transformer as given below -
import org.hibernate.transform.BasicTransformerAdapter;
public class FluentHibernateResultTransformer extends BasicTransformerAdapter {
private static final long serialVersionUID = 6825154815776629666L;
private final Class<?> resultClass;
private NestedSetter[] setters;
public FluentHibernateResultTransformer(Class<?> resultClass) {
this.resultClass = resultClass;
}
#Override
public Object transformTuple(Object[] tuple, String[] aliases) {
createCachedSetters(resultClass, aliases);
Object result = ClassUtils.newInstance(resultClass);
for (int i = 0; i < aliases.length; i++) {
setters[i].set(result, tuple[i]);
}
return result;
}
private void createCachedSetters(Class<?> resultClass, String[] aliases) {
if (setters == null) {
setters = createSetters(resultClass, aliases);
}
}
private static NestedSetter[] createSetters(Class<?> resultClass, String[] aliases) {
NestedSetter[] result = new NestedSetter[aliases.length];
for (int i = 0; i < aliases.length; i++) {
result[i] = NestedSetter.create(resultClass, aliases[i]);
}
return result;
}
}
And used this way inside the repository method -
#Override
public List<WalletVO> getWalletRelatedData(WalletRequest walletRequest,
Set<String> requiredVariablesSet) throws GenericBusinessException {
String query = getWalletQuery(requiredVariablesSet);
try {
if (query != null && !query.isEmpty()) {
SQLQuery sqlQuery = mEntityManager.unwrap(Session.class).createSQLQuery(query);
return sqlQuery.setResultTransformer(new FluentHibernateResultTransformer(WalletVO.class))
.list();
}
} catch (Exception ex) {
exceptionThrower.throwDatabaseException(null, false);
}
return Collections.emptyList();
}
It worked perfectly !!!

Try putting Column names and field names both in capital letters.

This exception occurs when the class that you specified in the AliasToBeanResultTransformer does not have getter for the corresponding columns. Although the exception details from the hibernate are misleading.

Java Reflection to set Value for the java pojo

Goal :
set value for the given java bean at run time and generate JSON Object or JSON array.
the above is my goal and i have tried some thing like the below :
package com.hexgen.tools;
import java.lang.reflect.Method;
import com.google.gson.Gson;
public class ConvertPOJOToJSON {
public Object creatJSONObject(String className) throws IllegalArgumentException, IllegalAccessException, InstantiationException, Exception {
Class<?> objectClass = null;
Object clsObject =null;
try {
objectClass = Class.forName(className);
clsObject = objectClass.newInstance();
for(Method m : objectClass.getMethods())
if (m.getName().startsWith("set") && m.getParameterTypes().length == 1 && m.getModifiers()==23)
m.invoke(clsObject, "myValue");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return clsObject;
}
public static void main(String[] args) {
Gson gson = new Gson();
ConvertPOJOToJSON pojoToJSON = new ConvertPOJOToJSON();
try {
System.out.println("JSON OBJECT : "+gson.toJson(pojoToJSON.creatJSONObject("com.hexgen.ro.request.CreateRequisitionRO")));
} catch (Exception e) {
e.printStackTrace();
}
}
}
The Output of the above class :
JSON OBJECT : {"isAllocable":false}
there are many fields in the class i gave com.hexgen.ro.request.CreateRequisitionRO but only one boolean value is set to false and returns the value.
i have some constant value to set for the fields say if the field type is Integer than set some default integer value like so
EDIT :
I have created a enum like the following :
package com.hexgen.tools;
import java.math.BigDecimal;
import java.math.BigInteger;
import org.joda.time.LocalDate;
public enum DefaultParamValues {
STRING("HEXGEN"),
INTEGER(123),
DATE(new LocalDate()),
BOOLEAN(true),
LONGVALUE(123123),
BIGDECIMAL(new BigDecimal("100000"));
private String defaultString;
private int defaultInteger;
private LocalDate defaultDate;
private boolean defaultBoolean;
private long defaultLong;
private BigDecimal defaultBigDecimal;
private DefaultParamValues(String strDefaultValue) {
defaultString = strDefaultValue;
}
private DefaultParamValues(int intDefaultValue) {
defaultInteger = intDefaultValue;
}
private DefaultParamValues(LocalDate dateDefaultValue) {
defaultDate = dateDefaultValue;
}
private DefaultParamValues(boolean booleanDefaultValue) {
defaultBoolean = booleanDefaultValue;
}
private DefaultParamValues(long longDefaultValue) {
defaultLong = longDefaultValue;
}
private DefaultParamValues(BigDecimal bigIntegerDefaultValue) {
defaultBigDecimal = bigIntegerDefaultValue;
}
public String getDefaultString() {
return defaultString;
}
public int getDefaultInt() {
return defaultInteger;
}
public LocalDate getDefaultDate() {
return defaultDate;
}
public boolean getDefaultBoolean() {
return defaultBoolean;
}
public long getDefaultLong() {
return defaultLong;
}
public BigDecimal getDdefaultBigDecimal() {
return defaultBigDecimal;
}
}
created one more method like the following :
public Object creatObjectWithDefaultValue(String className) throws IllegalArgumentException, IllegalAccessException, InstantiationException {
DefaultParamValues defaultParamValues = null;
Class<?> objectClass = null;
Object clsObject =null;
try {
objectClass = Class.forName(className);
clsObject = objectClass.newInstance();
Field[] fields = objectClass.getDeclaredFields();
for(Field f:fields){
if(!f.isAccessible()){
f.setAccessible(true);
Class<?> type = f.getType();
if(! Modifier.isFinal(f.getModifiers()) && type.equals(Integer.class)){
f.set(clsObject, defaultParamValues.INTEGER);
} else if( !Modifier.isFinal(f.getModifiers()) && type.equals(java.math.BigDecimal.class)){
f.set(clsObject, defaultParamValues.BIGDECIMAL);
} else if(! Modifier.isFinal(f.getModifiers()) && type.equals(org.joda.time.LocalDate.class)){
f.set(clsObject,defaultParamValues.DATE);
} else if(! Modifier.isFinal(f.getModifiers()) && type.equals(boolean.class)){
f.set(clsObject, defaultParamValues.BOOLEAN);
} else if(! Modifier.isFinal(f.getModifiers()) && type.equals(java.lang.String.class)){
f.set(clsObject, defaultParamValues.STRING);
}
else if(! Modifier.isFinal(f.getModifiers()) && type.equals(long.class)){
f.set(clsObject, defaultParamValues.LONGVALUE);
}
//f.setAccessible(false);
}
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return clsObject;
}
to set the default values but i get the following exception:
Exception in thread "main" java.lang.IllegalArgumentException: Can not set java.math.BigDecimal field com.hexgen.ro.request.CreateRequisitionRO.transSrlNo to com.hexgen.tools.DefaultParamValues
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:146)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:150)
at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:63)
at java.lang.reflect.Field.set(Field.java:657)
at com.hexgen.tools.JsonConverter.creatObjectWithDefaultValue(JsonConverter.java:93)
at com.hexgen.tools.JsonConverter.main(JsonConverter.java:201)
Please help me to find the solution.
Best Regards

If your looking for a lightweight library which can do this and more including allowing you to do your own filtering to find Methods/Fields. I wrote an open source library which has no 3rd party dependencies and is available on Maven Central.
Checkout https://github.com/gondor/reflect
As for your issue it appears your setting the "Enum" constant and not the inner value of the enum. Wouldn't it DefaultParamValues.BIGDECIMAL.getDdefaultBigDecimal()