How to handle special characters and encoding while parsing and generating JSON using GSON in Kotlin Android

How to handle special characters and encoding while parsing and generating JSON using GSON in Kotlin Android.

Here's a step-by-step tutorial on how to handle special characters and encoding while parsing and generating JSON using GSON in Kotlin Android.

Step 1: Add GSON dependency To get started, you need to add the GSON dependency to your project. Open your project's build.gradle file and add the following line under the dependencies section:

implementation 'com.google.code.gson:gson:2.8.7'

Step 2: Create a data class Next, you need to create a data class that represents the structure of your JSON data. This class will be used by GSON for parsing and generating JSON. For example, let's create a simple data class representing a person:

data class Person(
    val name: String,
    val age: Int,
    val address: String
)

Step 3: Parsing JSON with special characters If your JSON contains special characters, such as Unicode characters or escape sequences, you need to properly handle them while parsing. Here's an example of how to parse JSON with special characters using GSON:

val jsonString = "{\"name\":\"John Doe\",\"age\":30,\"address\":\"123 \\u00C9lm Street\"}"

val gson = Gson()
val person = gson.fromJson(jsonString, Person::class.java)

println(person.name)     // Output: John Doe
println(person.age)      // Output: 30
println(person.address)  // Output: 123 Élm Street

In the above example, the JSON string contains a Unicode escape sequence \u00C9 which represents the character É. GSON automatically handles the decoding of the escape sequence and assigns the decoded value to the address property of the Person object.

Step 4: Generating JSON with special characters When generating JSON with special characters, GSON automatically escapes them for you. Here's an example of how to generate JSON with special characters using GSON:

val person = Person("John Doe", 30, "123 Élm Street")

val gson = Gson()
val jsonString = gson.toJson(person)

println(jsonString)

The output will be:

{"name":"John Doe","age":30,"address":"123 \u00C9lm Street"}

In the generated JSON string, the special character É is properly escaped as \u00C9.

Step 5: Customizing GSON's behavior If you need to customize GSON's behavior for handling special characters, you can create a custom Gson instance and configure it accordingly. For example, you can specify a custom character set for encoding and decoding JSON strings:

val charset = Charsets.UTF_8
val gson = GsonBuilder()
    .setCharset(charset)
    .create()

In the above example, we're setting the character set to UTF-8. You can choose a different character set based on your requirements.

That's it! You now know how to handle special characters and encoding while parsing and generating JSON using GSON in Kotlin Android.