How to convert xml to json java

Converting Between XML and JSON Using JAXB and Jackson

JAXB converts XML to Java and Jackson handles the Java to JSON Conversion

“You only live once, but if you do it right, once is enough.” ― Mae West

1. Introduction

In a previous article we covered the basics of using JAXB with its annotations to convert java objects to XML and back. In this article, we take a look at converting from XML to JSON and back, using jackson for the JSON conversion.

We use the same example XML for illustrating the difference in conversion of XML versus JSON. Here is a snippet of the XML:

2. Java Object Model

We use the following classes for converting to and from XML.

2.1. The Catalog class

The Catalog class is the same as earlier. It works both for converting XML using JAXB as well as converting JSON using Jackson. No Jackson specific annotations required here.

2.2. The Book class

The Book class requires a few changes. First off let us attempt to use it as is and see if it works. Here is the Book class defined as before:

3. Converting XML to JSON

And here is how we convert XML to JSON. First load the XML using JAXB.

Next is to serialize the java object to JSON.

The conversion proceeds without exceptions and we get the following JSON output.

Immediately, we notice that the file publish_date in XML is serialized as pubdate in JSON since that is the field name in the java class. Also, full details of the field values for pubdate are serialized, whereas we would like just the date in the format 2000-10-01.

4. Converting JSON to XML

Let us attempt to convert this JSON back into XML and see if it works. The code for doing so basically reverses what we did above: use Jackson to deserialize JSON into our java objects, and serialize that data into XML using JAXB.

On running this code, however, we get the following error:

On deciphering the somewhat complex message shown above, we come to the conclusion that Jackson failed trying to convert the pubdate JSON values into a LocalDate instance – there are no constructors available for doing so.

So what do we do?

5. Changing the JSON Field Name

First let us change the JSON field name from pubdate to publish_date. This is accomplished very easily using the Jackson annotations in the Book class as shown below.

These annotations will take care of the field name both for serialization as well as deserialization.

6. Using Adapter Classes to Control JSON Format

Since the LocalDate class does not have a constructor accepting a String, we need to use adapter classes for (de-)serialization.

Here is the class to be used for serialization. It uses LocalDate.toString() to generate a string representation of the date in the format 2000-10-01, rather than the long format with all the fields shown previously.

And the corresponding deserializer is shown below. It uses LocalDate.parse() to convert from a date string in the format 2000-10-01 to a LocalDate instance.

Once these classes are defined, we need to tell Jackson to use them. One way to do it is to use annotations in the Book class.

Once these changes are implemented, conversion to JSON proceeds smoothly with the following changes: 1. Using publish_date instead of pubdate as before 2. The field publish_date formatted as a string.

The conversion from JSON to XML is similarly correct.

And that is one way you can convert XML to JSON and back!

Conclusion

When you need to convert XML to JSON and back, you can use JAXB with Jackson for the conversion. JAXB converts XML to java objects, and Jackson converts the same java objects to JSON. We did need a few adjustements to get the format we desired, though.

How to Convert JSON to XML or XML to JSON in Java

In this tutorial you will learn how to convert json to xml or xml to json in java.

While programming we may come across a situation where we have to convert json to xml or vice versa. JSON.org provides a library that can be used for this conversion process in just one line of code.

Below I have shared examples to do this.

Download the json java library from below link and import in your project.

If you don’t know how to import a library in java then you can read below article.

Convert JSON to XML in Java

Just pass the given json object in XML.toString() method to convert it into xml data.

Output

Convert XML to JSON in Java

Just pass the xml data into XML.toJSONObject() method to convert it into json object.

Output

Programming Tip: Level up your programming skills by moving your software development/testing environment into the cloud with innovative hosted citrix vdi from CloudDeskopOnline with remote accessibility to essential programming tools on any device(PC/android/iOS). Looking for a dedicated server for your project? Try out dedicated gpu hosting and Enterprise E3 suite from Apps4Rent to gear up your work productivity.

You May Also Like:

13 comments

Is there any way to maintain order while transforming JSON to XML. I have a Input JSON file. But when I convert it into XML, the order will be changed. I was searching solution from past 2 days. I tried in mule as well as in Java but it won’t work. This is the Input JSON data.
<
“status” : “success”,
“response” : <
“p_status_msg” : <
“contact” : <
“contactlist” : [<
“address” : “90 Grove St., Newport ME 04953; United States of America”,
“grp” : “ADDRESS”,
“pidm” : “”,
“type” : “Home (preferred)”
>, <
“address” : “[email protected]”,
“grp” : “EMAIL”,
“pidm” : “”,
“type” : “Academy Email”
>, <
“address” : “[email protected]”,
“grp” : “EMAIL”,
“pidm” : “”,
“type” : “Email”
>, <
“address” : “(207) 341-3018”,
“grp” : “PHONE”,
“pidm” : “”,
“type” : “Cell Phone”
>
],
“contact” : <
“studentid” : “P000020581”,
“dateofbirth” : “07/07/1995”,
“firstname” : “John”,
“socialsecuritynumber” : “005961046”,
“gender” : “M”,
“middlename” : “Q.”,
“lastname” : “Adams”
>
>
>
>
>

Please help me out. Thanks.

Yes you can maintain the order.
Once the program gives you have the output result, copy and paste it a notepad and then cut paste the data to bring it in correct order.

Underscore-java library has methods xmlToJson and jsonToXml.

digitalheir/java-xml-to-json

Use Git or checkout with SVN using the web URL.

Work fast with our official CLI. Learn more.

Launching GitHub Desktop

If nothing happens, download GitHub Desktop and try again.

Launching GitHub Desktop

If nothing happens, download GitHub Desktop and try again.

Launching Xcode

If nothing happens, download Xcode and try again.

Launching Visual Studio Code

Your codespace will open once ready.

There was a problem preparing your codespace, please try again.

Latest commit

Git stats

Files

Failed to load latest commit information.

README.md

XML to terse JSON

This is a project to convert XML documents to JSON. It does this by taking a disciplined approach to create a terse JSON structure. The library has support for node types such as comments and processing instructions.

DTDs are experimentally supported (a node will be created for them), but entity references are unpacked, i.e., in XML becomes in JSON.

Another motivation was to have a more light-weight JSON serialization of XML, since lossless transformations tend to be wordy. In this library, we trade off some readability for a reduction in bytes. JSON output for this library is typically only slightly larger in bytesize than the XML input.

Download the latest JAR or grab from Maven:

How to Convert Data to JSON and XML in Java

The following four APIs will allow you to convert your data sets from Excel and CSV to JSON and XML.

Join the DZone community and get the full member experience.

Having your important data available to you whenever you need it will increase your efficiency and boost your overall productivity. For large amounts of data such as invoices or other tracked transactions that can be logged continuously for years, trying to find one instance in a massive Excel spreadsheet is not the ideal solution. Instead, by converting your data to JSON or XML, you can transfer these logs to a computer program that can then be accessed by anyone with permission and simplify the data retrieval process.

However, to do this, your data needs to be placed in a machine-readable format that will be easily understood by your computer systems. For example, much of your data is likely saved in an Excel or CSV file format, as these are the most familiar and user-friendly static data formats. However, data from these programs cannot be easily transferred to an online format that might be necessary for certain applications used by your organization. Thus, a data interchange format like JSON or XML is required for accessibility.

JavaScript Object Notation, or JSON, is a widely used data-interchange format used to store and exchange data for widescale usage. It is also a self-describing system, where the variables for your data can be created at will, without limiting factors. Our other option, Extensible Markup Language (XML), is like JSON in that both humans and computers can easily read it. Still, it mainly uses prescribed tags that divide information according to its traits. Thus, XML appears very similar to HTML in its code formatting. Though it uses more descriptive words than JSON, XML allows for higher specificity in how data is read by the computer, including improved metadata usability. In essence, when working on the browser-side, JSON is preferred, while XML is ideal for working server-side.

The following four APIs will allow you to convert your data sets from Excel and CSV to JSON and XML. This will allow you to improve the accessibility of your data and increase the efficiency with which your system receives, read, and process your information for further use.

Convert JSON to XML Java using Gson and JAXB with Example

Updated July 9, 2022

What is JSON?

JSON is an abbreviation for Javascript Object Notation, which is a form of data that follows a certain rule that most programming languages are currently readable. We can easily save it to a file or record in the database. JSON format uses key-value pairs to describe data.

In following the example, we define a JSON string that stores personal information:

So the syntax of JSON is very simple. Each data information will have two parts: key and value which correspond to the field name and its value in a certain record. But as further looking, there are a few things like this:

In this tutorial, you will learn-

What is XML?

XML stands for eXtensible Markup Language also called the extensible markup language proposed by the World Wide Web Consortium (https://www.w3.org/) to create other markup languages. This is a simple subset that can describe many different types of data, so it is very useful in sharing data between systems.

Tags in XML are often not predefined, but they are created according to user conventions. XML introduces new features based on the advantages of HTML.

There are some more useful XML-making features in diverse systems and solutions:

XML is built on a nested node structure. Each node will have an opening tag and a closing tag as follows:

In which:

At the top of each XML file you must declare a tag to indicate the version XML is in use. The syntax of the instruction tag:

What is Gson?

Gson (https://github.com/google/gson) is a java library that allows users to convert from a Java object to JSON string and also convert from a JSON string to Java object. Gson can work with arbitrary Java objects including existing objects without you having their source-code.

Since version 1.6, Gson introduces two new classes – JsonReader and JsonWriter to provide streaming processing on JSON data.

Gson streaming processing is fast. However you need to handle each pair (key => value) of processing JSON data.

What is JAXB?

JAXB stands for Java Architecture for XML Binding, which is a library that uses annotations to convert Java objects to XML content and vice versa. As JAXB is defined via a specification, we can use different implementations for this standard.

With JAXB, we often use following basic annotations, namely:

The syntax for general implementation is as follows. First, we will initialize the JAXBContext object with the MyObject object to convert.

In this JAXBContext object, it has a method to create an object that converts XML content to a Java object, Unmarshaller.

In this JAXBContext object, it has a method to create the object that converts the Java object to the XML content that is Marshaller.

How to convert XML to JSON?

We implement the example of XML – JSON conversion on the platform:

Step 1. Create project.
Create a new Java Project.

Create a new Java Project.

Step 2. Set Project name.
Set Project name is XmlToJsonExample.

Set Project name.

Step 3. Create a folder.
Create folder data/input containing two file sample.xml and sample.json.

Create folder data/input.

Let’s first define our XML with department, role and person properties.

Object Relationships.

Secondly, we define JSON having the same idea:

Step 4. Define object.
Define corresponding object classes in the package model.

XMLModel.java:

Step 5. Set up library.
Add and Set up library Gson 2.8.5 into Java Build Path.

Add library Gson 2.8.5 into Java Build Path.

Convert XML message to Java objects using JAXB

Firstly, we define performing classed in package service.

Define performing classes.

At the first step of the first process, we use technique Un-marshalling of JAXB.

Un-marshalling provides a client application the ability to convert XML data into JAXB derived Java objects.

We define function getObjectFromXmlFile to un-marshal our XML file back to a Java object. This function is defined in class XMLService.

We call the code above in class XmlToJsonService.

Then we go to next step.

Convert Java objects to JSON message using Gson

At this step, we define function writeDataToJsonFile to write data to the JSON file. This function is defined in class JsonService.

Note that to write a list of JSON strings, we use the function beginArray() and endArray(). Between these two functions, we write each JSON string.

We call the above code in class XmlToJsonService.

That’s the first process.

Convert JSON message to Java objects using Gson

At the first step of second process, we define function getDataFromJsonFile to read data from JSON file. This function is defined in class JsonService.

Note that to read a list of JSON strings, we use the function beginArray() and endArray(). Between these two functions, we read each JSON string.

We call the above code in class XmlToJsonService.

How to Convert Json to XML Java?

JSON to XML in JAVA is converted by using JSONObject json = new JSONObject(str); String xml = XML. If you have a valid dtd file or the xml file then it is very easy to transform json to xml and also xml to json.

Then we go to next step.

Convert Java objects to XML message using JAXB

At this step, we use technique Marshalling of JAXB.

Marshalling provides a client application the ability to convert a JAXB derived Java object tree into XML data.

We define function parseObjectToXm to marshall Java object to XML message. This function is defined in class

We call the above code in class XmlToJsonService.

That’s the second process.

Conclusion

In this tutorial, we briefly learned one way in which JAXB can read XML data and Gson write it to JSON. On the contrary, we also saw the way that Gson read JSON data and JAXB write it to XML.