In-depth understanding of the JSON In Java working principle in the Java library
In -depth understanding
Introduction:
In today's software development, cross -platform data exchange and transmission are a common demand.JSON (JavaScript Object Notation), as a lightweight data exchange format, has become a widely used standard.The Java class library provides rich support, so that developers can easily analyze and generate JSON data in the Java program.This article will explore the working principles of JSON in the Java class library, including related programming code and configuration.
1. The working principle of JSON in the Java library
The principle of JSON is very simple, and it represents data by key value pair.The JSON tools in the Java class library mainly involve the following two functions:
1. Analyze JSON data: convert the data of JSON format to the Java object in order to process it in the Java program.
2. Generate JSON data: transform Java objects into JSON format data to facilitate use in network transmission or storage.
2. JSON analysis work principle
The JSON analysis process mainly includes the following steps:
1. Read json data: Read JSON data from files, networks, or other data sources.
2. Analyze JSON data: convert the read JSON data to the Java object.
3. Use Java object: Use parsed Java objects to perform corresponding operations, such as obtaining field values, modifying field values, etc.
The following is a simple sample code, which demonstrates how to analyze JSON data in Java:
import org.json.JSONObject;
public class JsonParser {
public static void main(String[] args) {
String jsonStr = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";
// Analyze json data
JSONObject jsonObject = new JSONObject(jsonStr);
// Get the field value
String name = jsonObject.getString("name");
int age = jsonObject.getInt("age");
String city = jsonObject.getString("city");
// Output field value
System.out.println("Name: " + name);
System.out.println("Age: " + age);
System.out.println("City: " + city);
}
}
In the above example code, we first created a JSON string `jsonstr`, and then analyzed it with the` jsonObject` class to the Java object `jsonObject`.Next, we obtained the corresponding field value through methods such as `GetString` and` Getint` and output it to the console.
3. JSON generating the principle of working working
The JSON generation process mainly includes the following steps:
1. Create a Java object: generate the structure of JSON data as needed, and create a corresponding Java object.
2. Set the field value: Set the corresponding value for the field of the Java object.
3. Generate JSON data: transform the Java object to JSON format data.
The following is a simple example code. How to generate JSON data in Java:
import org.json.JSONObject;
public class JsonGenerator {
public static void main(String[] args) {
// Create jsonObject objects
JSONObject jsonObject = new JSONObject();
// Set the field value
jsonObject.put("name", "John");
jsonObject.put("age", 30);
jsonObject.put("city", "New York");
// Generate json data
String jsonString = jsonObject.toString();
// Output json data
System.out.println(jsonString);
}
}
In the above example code, we first created a `jsonObject` object` jsonObject`, and then use the `put` method to set the corresponding field value.Finally, the `tostring` method converts the` jsonObject` to the JSON string `jsonstring` and output it to the console.
Fourth, related configuration
When using the JSON tool in the Java class library, you need to ensure that the corresponding JSON library has been added to the dependence of the project.Common JSON libraries include `ORG.JSON`,` gson`, `jackson` and so on.You can choose a suitable JSON library according to your needs, and add corresponding dependencies in the project configuration file (such as Maven's pom.xml).
<dependencies>
<!-- org.json -->
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20210307</version>
</dependency>
<!-- gson -->
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.8</version>
</dependency>
<!-- Jackson -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.13.0</version>
</dependency>
</dependencies>
According to the JSON library you choose, you can import the corresponding class library in the code and use the API provided by the library to analyze and generate JSON data.
in conclusion:
Through the introduction of this article, we deeply understand the working principle of JSON in the Java class library.We understand the process of JSON's analysis and generation, and demonstrate how to use the JSON class library in the Java program.Through reasonable selection of the JSON library, we can handle JSON data more efficiently to meet the needs of cross -platform data exchange and transmission.
