I have an XML which looks like below
<Book>
<Name>Book1</Name>
<Cost>20$</Cost>
</Book>
I have used a Bean Class with properties name, cost and successfully unmarshaled the xml file contents to Book bean object.
Now I want to have multiple book objects in the same XML file like below.
<Books>
<Book>
...
</Book>
<Book>
...
</Book>
I know that I can create one more class with Name Books.java and have an arraylist of book objects annotated with #XmlElement tag and unmarshall it.
But, I don't want to waste one more public class for doing that.
Can anyone let me know if there is any other way of parsing that xml file with JaxB.
Thanks in advance.
Found the solution..
I can have a class like below. I can use List list; variable member within the same class Book.java instead of using one more public class Books.java.
#XmlRootElement(name = "Books")
#XmlAccessorType(XmlAccessType.FIELD)
public class BookBean {
private String name;
private String cost;
#XmlElement(name = "Books")
public List<BookBean> books;
public BookBean(){
}
public BookBean(String s1, String s2){
name=s1;
cost=s2;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCost() {
return cost;
}
public void setCost(String cost) {
this.cost = cost;
}
public List<BookBean> getBooks() {
return books;
}
public void setBooks(List<BookBean> books) {
this.books = books;
}
}
I have one class:
#XmlRootElement(name="pickup")
public class PickUp
{
#XmlAttribute(name="contactName")
public String contactName;
#XmlAttribute(name="phoneNumber")
public String phoneNumber;
#XmlAttribute(name="pickupDate")
public String pickupDate;
#XmlAttribute(name="pickupTime")
public String pickupTime;
#XmlAttribute(name="closingTime")
public String closingTime;
#XmlAttribute(name="location")
public String location;
}
This will generate XMl like this:
<Pickup contactName="Test Name" phoneNumber="888-888-8888" pickupDate="2009-08-03" pickupTime="16:30" closingTime="17:45" location="Front Door"/>
This is working perfect, but with same code i also want to generate Xml like below:
<Pickup>
<contactName>Test Name</contactName>
<phoneNumber>888-888-8888</phoneNumber>
<pickupDate>2009-08-03</pickupDate>
<pickupTime>16:30</pickupTime>
<closingTime>17:45</closingTime>
<location>Front Door</location>
</Pickup>
I can do this by creating another class with #xmlElement but i want to use same class for this.
Please help me.
I found this https://stackoverflow.com/a/33096124/1976843 answer that can help you.
If you want to keep using jaxb you will need to write your own AnnotationReader
Your are using tags for XML attributes. Use #XmlElement tags to generate the XML in your required format you should give the tags as
#XmlElement
public String getContactName() {
return contactName;
}
public void setcontactName(String name) {
this.contactName= name;
}
#XmlElement
public String getphoneNumber() {
return phoneNumber;
}
public void setphoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
No need to create a new class. You can do changes in your original class for xml element.
Consider two isomorphous XML schemas. By isomorphism here I mean that these two schemas have identical structures except attributes and tags names. More specifically I have live example when was schema, say A, and its copy B, where all tags and attribute names were translated from English into national lamguage equivalents.
For example, as input we can have two different variants of one object:
<tag_1_v1>
<tag_2_v1 id="blabla" name="xxxxx">
Some value1
</tag_2_v1>
<tag_3_v1 id="alalala" name="yyyyy">
Some value2
</tag_3_v1>
</tag_1_v1>
and
<tag_1_v2>
<tag_2_v2 special_id_2="blabla" name="xxxxx">
Some value1
</tag_2_v2>
<tag_3_v2 id="alalala" special_name_2="yyyyy">
Some value2
</tag_3_v2>
</tag_1_v2>
The problem is to map these two schemas on single class structure, say
class Tag1 {
Tag2 tag2;
Tag3 tag3;
}
class Tag2 {
String id;
String name;
String value;
}
class Tag3 {
String id;
String name;
String value;
}
There are various ideas how to workaround this issue, but all of them aren't so convinient, as any possibility to use single JAXB annotation scheme on same class structure. They are:
create two different class-sets and then copy values from objects of
one schema into another;
create own SAX parser implementation and "translate" inside it tag and attribute names into appropriate ones;
use own preprocessor of XML and use string replacement (will not work if id and attributes name aren't identical within all schema).
Since each <tag_i> can have different attributes, a clean solution would be to use inheritance:
Create an abstract class Tag1 that is inherited by Tag1V1 and Tag1V2. Factor all the common code into Tag1.
The same would go Tag2 and Tag3.
To get you started, here would be an implementation of Tag2:
#XmlRootElement
#XmlSeeAlso({Tag2V1.class, Tag2V2.class})
abstract class Tag2 {
private String name;
private String content;
#XmlAttribute(name = "name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#XmlValue
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
#XmlRootElement(name = "tag_2_v1")
class Tag2V1 extends Tag2 {
private String id;
#XmlAttribute(name = "id")
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}
#XmlRootElement(name = "tag_2_v2")
class Tag2V2 extends Tag2 {
private String specialId2;
#XmlAttribute(name = "special_id_2")
public String getSpecialId2() {
return specialId2;
}
public void setSpecialId2(String specialId2) {
this.specialId2 = specialId2;
}
}
May be I am repeating this question as compared to previous question(Define namespaces tags so that generated XML have those tags?), but since in my previous question this scope gets limited to XStream that is why I need to ask this new question.
I have two classes People.java and PeopleMain.java
People.java
package com.test;
public class People {
private String name;
private String age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
}
PeopleMain.java
package com.test;
import com.thoughtworks.xstream.XStream;
public class PeopleMain {
public static void main(String args[]){
People p= new People();
p.setAge("21");
p.setName("Manish Sharma");
String xml = //JAXB code to get xml from Person p object
System.out.println(xml);
}
}
My output on console on running PeopleMain.java comes as:
<com.test.People>
<name>Manish Sharma</name>
<age>21</age>
</com.test.People>
but I want an output as
<People xmlns:ns2="http://example.com/foo" xmlns:ns3="http://example.com/bar">
<ns2:name>Manish Sharma</ns2:name>
<ns3:age>21</ns3:age>
</People>
What changes should I make in my People.java file to get the desired output?
You can do the following and specify the namespace on the #XmlElement annotation:
import javax.xml.bind.annotation.*;
#XmlRootElement(name="People")
#XmlAccessorType(XmlAccessType.FIELD)
public class People {
#XmlElement(namespace="http://example.com/foo")
private String name;
#XmlElement(namespace="http://example.com/bar")
private int age;
}
For More Information
http://blog.bdoughan.com/2010/08/jaxb-namespaces.html
http://blog.bdoughan.com/2011/11/jaxb-and-namespace-prefixes.html
http://blog.bdoughan.com/2010/10/how-does-jaxb-compare-to-xstream.html
Recently I've started hearing about "POJOs" (Plain Old Java Objects). I googled it, but still don't understand the concept well. Can anyone give me a clear description of a POJO?
Consider a class "Person" with variables "id, name, address, salary" -- how would I create a POJO for this scenario? Is the code below a POJO?
public class Person {
//variables
People people = new People();
private int id;
private String name;
private String address;
private int salary;
public int getId() {
return id;
}
public String getName() {
return name;
}
public String getAddress() {
return address;
}
public int getSalary() {
return salary;
}
public void setId() {
this.id = id;
}
public void setName() {
this.name = name;
}
public void setAddress() {
this.address = address;
}
public void setSalary() {
this.salary = salary;
}
}
A POJO is just a plain, old Java Bean with the restrictions removed. Java Beans must meet the following requirements:
Default no-arg constructor
Follow the Bean convention of getFoo (or isFoo for booleans) and setFoo methods for a mutable attribute named foo; leave off the setFoo if foo is immutable.
Must implement java.io.Serializable
POJO does not mandate any of these. It's just what the name says: an object that compiles under JDK can be considered a Plain Old Java Object. No app server, no base classes, no interfaces required to use.
The acronym POJO was a reaction against EJB 2.0, which required several interfaces, extended base classes, and lots of methods just to do simple things. Some people, Rod Johnson and Martin Fowler among them, rebelled against the complexity and sought a way to implement enterprise scale solutions without having to write EJBs.
Martin Fowler coined a new acronym.
Rod Johnson wrote "J2EE Without EJBs", wrote Spring, influenced EJB enough so version 3.1 looks a great deal like Spring and Hibernate, and got a sweet IPO from VMWare out of it.
Here's an example that you can wrap your head around:
public class MyFirstPojo
{
private String name;
public static void main(String [] args)
{
for (String arg : args)
{
MyFirstPojo pojo = new MyFirstPojo(arg); // Here's how you create a POJO
System.out.println(pojo);
}
}
public MyFirstPojo(String name)
{
this.name = name;
}
public String getName() { return this.name; }
public String toString() { return this.name; }
}
POJO:- POJO is a Java object not bound by any restriction other than those forced by the Java Language Specification.
Properties of POJO
All properties must be public setter and getter methods
All instance variables should be private
Should not Extend prespecified classes.
Should not Implement prespecified interfaces.
Should not contain prespecified annotations.
It may not have any argument constructors
Example of POJO
public class POJO {
private String value;
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
A POJO is a Plain Old Java Object.
From the wikipedia article I linked to:
In computing software, POJO is an
acronym for Plain Old Java Object. The
name is used to emphasize that a given
object is an ordinary Java Object, not
a special object, and in particular
not an Enterprise JavaBean
Your class appears to already be a POJO.
POJO class acts as a bean which is used to set and get the value.
public class Data
{
private int id;
private String deptname;
private String date;
private String name;
private String mdate;
private String mname;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getDeptname() {
return deptname;
}
public void setDeptname(String deptname) {
this.deptname = deptname;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getMdate() {
return mdate;
}
public void setMdate(String mdate) {
this.mdate = mdate;
}
public String getMname() {
return mname;
}
public void setMname(String mname) {
this.mname = mname;
}
}
When you aren't doing anything to make your class particularly designed to work with a given framework, ORM, or other system that needs a special sort of class, you have a Plain Old Java Object, or POJO.
Ironically, one of the reasons for coining the term is that people were avoiding them in cases where they were sensible and some people concluded that this was because they didn't have a fancy name. Ironic, because your question demonstrates that the approach worked.
Compare the older POD "Plain Old Data" to mean a C++ class that doesn't do anything a C struct couldn't do (more or less, non-virtual members that aren't destructors or trivial constructors don't stop it being considered POD), and the newer (and more directly comparable) POCO "Plain Old CLR Object" in .NET.
According to Martin Fowler
The term was coined while Rebecca Parsons, Josh MacKenzie and I were preparing for a talk at a conference in September 2000. In the talk, we were pointing out the many benefits of encoding business logic into regular java objects rather than using Entity Beans. We wondered why people were so against using regular objects in their systems and concluded that it was because simple objects lacked a fancy name. So we gave them one, and it’s caught on very nicely.
Generally, a POJO is not bound to any restriction and any Java object can be called a POJO but there are some directions. A well-defined POJO should follow below directions.
Each variable in a POJO should be declared as private.
Default constructor should be overridden with public accessibility.
Each variable should have its Setter-Getter method with public accessibility.
Generally POJO should override equals(), hashCode() and toString() methods of Object (but it's not mandatory).
Overriding compare() method of Comparable interface used for sorting (Preferable but not mandatory).
And according to Java Language Specification, a POJO should not have to
Extend pre-specified classes
Implement pre-specified interfaces
Contain pre-specified annotations
However, developers and frameworks describe a POJO still requires the use prespecified annotations to implement features like persistence, declarative transaction management etc. So the idea is that if the object was a POJO before any annotations were added would return to POJO status if the annotations are removed then it can still be considered a POJO.
A JavaBean is a special kind of POJO that is Serializable, has a no-argument constructor, and allows access to properties using getter and setter methods that follow a simple naming convention.
Read more on Plain Old Java Object (POJO) Explained.
there are mainly three options are possible for mapping purpose
serialize
XML mapping
POJO mapping.(Plain Old Java Objects)
While using the pojo classes,it is easy for a developer to map with the database.
POJO classes are created for database and at the same time value-objects classes are created with getter and setter methods that will easily hold the content.
So,for the purpose of mapping in between java with database, value-objects and POJO classes are implemented.
import java.io.Serializable;
public class Course implements Serializable {
protected int courseId;
protected String courseName;
protected String courseType;
public Course() {
courseName = new String();
courseType = new String();
}
public Course(String courseName, String courseType) {
this.courseName = courseName;
this.courseType = courseType;
}
public Course(int courseId, String courseName, String courseType) {
this.courseId = courseId;
this.courseName = courseName;
this.courseType = courseType;
}
public int getCourseId() {
return courseId;
}
public void setCourseId(int courseId) {
this.courseId = courseId;
}
public String getCourseName() {
return courseName;
}
public void setCourseName(String courseName) {
this.courseName = courseName;
}
public String getCourseType() {
return courseType;
}
public void setCourseType(String courseType) {
this.courseType = courseType;
}
#Override
public int hashCode() {
return courseId;
}
#Override
public boolean equals(Object obj) {
if (obj != null || obj instanceof Course) {
Course c = (Course) obj;
if (courseId == c.courseId && courseName.equals(c.courseName)
&& courseType.equals(c.courseType))
return true;
}
return false;
}
#Override
public String toString() {
return "Course[" + courseId + "," + courseName + "," + courseType + "]";
}
}
public class UserInfo {
String LoginId;
String Password;
String FirstName;
String LastName;
String Email;
String Mobile;
String Address;
String DOB;
public String getLoginId() {
return LoginId;
}
public void setLoginId(String loginId) {
LoginId = loginId;
}
public String getPassword() {
return Password;
}
public void setPassword(String password) {
Password = password;
}
public String getFirstName() {
return FirstName;
}
public void setFirstName(String firstName) {
FirstName = firstName;
}
public String getLastName() {
return LastName;
}
public void setLastName(String lastName) {
LastName = lastName;
}
public String getEmail() {
return Email;
}
public void setEmail(String email) {
Email = email;
}
public String getMobile() {
return Mobile;
}
public void setMobile(String mobile) {
Mobile = mobile;
}
public String getAddress() {
return Address;
}
public void setAddress(String address) {
Address = address;
}
public String getDOB() {
return DOB;
}
public void setDOB(String DOB) {
this.DOB = DOB;
}
}
File-setting-plugins-Browse repositories
Search RoboPOJOGenerator and install, Restart Android studio
Open Project and right click on package select on Generate POJO from JSON
Paste JSON in dialogbox and select option according your requirements
Click on Generate button
If a class is not bogged down from a framework or a library, then an object created from that class is recognized as a POJO.
Let's see some examples:
class MyServlet extends HttpServlet{
//....
}
The sole meaning of MyServlet class is given by the HttpServlet class. Therefore the objects created from the MyServlet are not POJOs.
class MyClass implements Serializable{
//...
}
The Serializable interface does not give a meaning to the class MyClass. Therefore the objects created from the MyClass are POJOs.