Jackson JSON Views

17 Mar 2025 | 6 分钟阅读

JSON Views 是 Jackson 的另一个重要组成部分。JSON Views 也用于序列化和反序列化 Java 对象。我们使用 @JsonView 注释在序列化/反序列化时自定义视图。

在本节中，我们将了解如何使用 JSON Views 执行序列化/反序列化，以及如何自定义视图。

使用 JSON Views 进行序列化

为了使用 @JsonView 序列化对象，我们首先创建一个视图，然后我们将使用它进行序列化。让我们举个例子来理解如何使用 JSON View 序列化一个对象。

JSONViewExample1.java

// import  required classes and package if any
import java.util.Scanner;
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;

// create class JSONViewExample1 to serialize an object using JSON View
public class JSONViewExample1 {
	// main() method start
	@SuppressWarnings("deprecation")
	public static void main(String args[]) throws JsonProcessingException {
		String id, name;
		// create an instance of Scanner class
		Scanner sc = new Scanner(System.in);
		
		System.out.println("Enter Student Id: ");
		id = sc.nextLine();
		
		System.out.println("Enter Student Name: ");
		name = sc.nextLine();
		
		// close Scanner class object
		sc.close();
		
		// create Student object
		Student std = new Student(id, name);

		// create an instance of ObjectMapper class
	    ObjectMapper mapper = new ObjectMapper();
	    
	    // disable DEFAULT_VIEW_INCLUSION mapper feature
	    mapper.disable(MapperFeature.DEFAULT_VIEW_INCLUSION);

	    String result = mapper
	    		.writerWithView(Views.Public.class)
	    		.writeValueAsString(std);
	    
	    System.out.println("Java object after serializing:"+result);
		
	}
	
}

// create class Student
class Student {
	
	// instance variable
    	public String stdId;

    	// instance variable with @JsonView
    	@JsonView(Views.Public.class)
    	public String stdName;
    
    	// default constructor
    	Student(){
    		this.stdId = null;
    		this.stdName = null;
    	}
    
    	// parameterized constructor
    	Student(String stdId, String stdName){
    		this.stdId = stdId;
    		this.stdName = stdName;
    	}
}

// create class for View
class Views {
	// create class public
    	public static class Public {
    	}
}

输出

通过使用多个 JSON Views，我们也可以在 Java 中序列化一个对象。在这里，我们创建一个视图，其中 Internal 视图扩展到 Public 视图。所以，Views 类看起来像这样

public class Views {
	public static class Public {
    	}

    	public static class Internal extends Public {
    	}
}

我们将修改 Student 类。在 Student 类中，stdId 和 stdName 字段将包含在 Public 视图中。我们创建一个新字段，即 course，它将被包含在 Internal 视图中。所以，我们的 Student 类看起来像这样

public class Student{
 
    	@JsonView(Views.Public.class)
    	public int stdId;

    	@JsonView(Views.Public.class)
    	public String stdName;

    	@JsonView(Views.Internal.class)
    	public String course;
}

现在，让我们举个例子来理解我们如何使用多个 JSON Views 序列化一个对象

JSONViewExample2.java

//import  required classes and package if any
import java.util.Scanner;
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;

//create class JSONViewExample2 to serialize an object using multiple JSON Views
public class JSONViewExample2 {
	
	// main() method start
	@SuppressWarnings("deprecation")
	public static void main(String args[]) throws JsonProcessingException {
		
		String id, name, course;
		
		// create an instance of Scanner class
		Scanner sc = new Scanner(System.in);
		
		System.out.println("Enter Student Id: ");
		id = sc.nextLine();
		
		System.out.println("Enter Student Name: ");
		name = sc.nextLine();
		
		System.out.println("Enter Course Name: ");
		course = sc.nextLine();
		
		// close Scanner class object
		sc.close();
		
		// create Student object
		Student std = new Student(id, name, course);

		// create an instance of ObjectMapper class
	    	ObjectMapper mapper = new ObjectMapper();
	    
	    	// disable DEFAULT_VIEW_INCLUSION mapper feature
	    	mapper.disable(MapperFeature.DEFAULT_VIEW_INCLUSION);

	    	String result = mapper
	    		.writerWithView(Views.Public.class)
	    		.writeValueAsString(std);
	    
	    System.out.println("Java object after serializing:"+result);
		
	}
	
}

//create class Student
class Student {

	@JsonView(Views.Public.class)
	public String stdId;

	@JsonView(Views.Public.class)
	public String stdName;

	@JsonView(Views.Internal.class)
	public String course;
 
	// default constructor
	Student(){
		this.stdId = null;
		this.stdName = null;
		this.course = null;
	}
 
	// parameterized constructor
	Student(String stdId, String stdName, String course){
		this.stdId = stdId;
		this.stdName = stdName;
		this.course = course;
	}
}

//create class for View
class Views {
	public static class Public {
    
	}
	
	public static class Internal extends Public {
    
	}
}

输出

使用 JSON Views 进行反序列化

就像序列化一样，我们也可以通过使用 JSON Views 将 JSON 字符串反序列化为 Java 对象。让我们举个例子来理解如何使用 JSON Views 完成反序列化。

JSONViewExample3.java

//import  required classes and package if any
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

//create class JSONViewExample3 to deserialize JSON string into POJO by using JSON Views
public class JSONViewExample3 {
	
	// main() method start
	public static void main(String args[]) throws JsonMappingException, JsonProcessingException{
		
		// JSON string to parse
		String jsonString = "{\"stdId\":\"121\", \"stdName\":\"Nicholas\"}";

		// create an instance of ObjectMapper class
	    	ObjectMapper mapper = new ObjectMapper();
	    
	    	// deserialize JSON string in Java object by using Jackson View
	    	Student std = mapper
	    		.readerWithView(Views.Public.class)
	    		.forType(Student.class)
	    		.readValue(jsonString);
		
	    	// print student Id and Name
	    	System.out.println("Student Id: "+std.stdId);
	    	System.out.println("Student Name: "+std.stdName);
	}
	
}

//create class Student
class Student {
	
	// instance variable
	public String stdId;

	// instance variable with @JsonView
	@JsonView(Views.Public.class)
	public String stdName;
 
	// default constructor
	Student(){
		this.stdId = null;
		this.stdName = null;
	}
 
	// parameterized constructor
	Student(String stdId, String stdName){
		this.stdId = stdId;
		this.stdName = stdName;
	}
}

//create class for View
class Views {
	// create class public
	public static class Public {
	}
}

输出

使用自定义 JSON Views 进行序列化

我们还可以通过使用自定义 JSON View 来 Java 对象。为了使用自定义 JSON View 序列化 Java 对象，我们首先使用 BeanPropertyWriter 自定义 JSON 视图。我们通过扩展 BeanPropertyWriter 来创建 65UpperCasingWriter 类，用于将学生姓名转换为大写。

让我们创建 UpperCasingWriter 类，用于将学生姓名转换为大写。

UpperCasingWriter.java

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;

// create class UpperCasingWriter to transform student name to upper case
public class UpperCasingWriter extends BeanPropertyWriter {
	
	// create a variable of type BeanPropertyWriter
    	BeanPropertyWriter writer;

    	// parameterized constructor of UpperCasingWriter
    	public UpperCasingWriter(BeanPropertyWriter writer) {
        
    		super(writer);
        	this.writer = writer;
    	}

    	// override serializeAsField() method of BeanPropertyWriter
    	@Override
    	public void serializeAsField(Object bean, JsonGenerator generator, SerializerProvider provider) throws Exception {
    	
    		// get student name from Object and store it to a variable of type String
        	String name = ((Student) bean).stdName;
        
        	// change name to upper case if it is not null
        	name = (name == null) ? "" : name.toUpperCase();
        
        	// write stdName in JSON by using generator
        	generator.writeStringField("stdName", name);
    	}
}

现在，我们将创建一个自定义修改器，以使用我们的 CustomCasingWriter 设置学生姓名 BeanPropertyWriter。

CustomBeanSerializerModifier.java

// import required classes and package if any
import java.util.List;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.SerializationConfig;
import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;
import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;

// create class CustomBeanSerializerModifier to set the student name BeanPropertyWriter with our custom UpperCasingWriter
public class CustomBeanSerializerModifier extends BeanSerializerModifier{

	// override changeProperties method of BeanSerializerModifier
    	@Override
    	public List<BeanPropertyWriter> changeProperties( SerializationConfig configObj, BeanDescription beanDescObj, 
    		List<BeanPropertyWriter> beanProperties) {
    	
    		// use for loop for iterating bean properties
    		for (int i = 0; i < beanProperties.size(); i++) {
    		
    			//get BeanPropertyWriter by using the get() method of List and store it into a variable of type BeanPropertyWriter
    			BeanPropertyWriter writer = beanProperties.get(i);
    		
    			// check whether the writer name equals to stdName or not
    			if (writer.getName() == "stdName") {
    			
    				// set UpperCasingWriter by using set method
                		beanProperties.set(i, new UpperCasingWriter(writer));
            		}
        	}
    		// return bean properties
        	return beanProperties;
    	}
}

让我们举个例子来理解如何使用自定义 JSON View 完成序列化。

JSONViewExample4.java

//import  required classes and package if any
import java.util.Scanner;
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ser.BeanSerializerFactory;
import com.fasterxml.jackson.databind.ser.SerializerFactory;

//create class JSONViewExample4 to serialize an object using the customize JSON Views
public class JSONViewExample4 {
	
	// main() method start
	public static void main(String args[]) throws JsonProcessingException {
		
		String id, name, course;
		
		// create an instance of Scanner class
		Scanner sc = new Scanner(System.in);
		
		System.out.println("Enter Student Id: ");
		id = sc.nextLine();
		
		System.out.println("Enter Student Name: ");
		name = sc.nextLine();
		
		System.out.println("Enter Course Name: ");
		course = sc.nextLine();
		
		// close Scanner class object
		sc.close();
		
		// create Student object
		Student std = new Student(id, name, course);

		// create an instance of SerializerFactory by using BeanSerializerFactory and CustomBeanSerializerModifier
		SerializerFactory factory = BeanSerializerFactory.instance
				.withSerializerModifier(new CustomBeanSerializerModifier());
			
		// create an instance of ObjectMapper class
		ObjectMapper mapper = new ObjectMapper();
		
		// set serializer factory to the maaper
	    	mapper.setSerializerFactory(factory);

	    	String jsonString = mapper.writerWithView(Views.Public.class).writeValueAsString(std);
	    
	    	System.out.println("Java object after serializing: "+jsonString);
		
	}
	
}

//create class Student
class Student {

	@JsonView(Views.Public.class)
	public String stdId;

	@JsonView(Views.Public.class)
	public String stdName;

	@JsonView(Views.Internal.class)
	public String course;

	// default constructor
	Student(){
		this.stdId = null;
		this.stdName = null;
		this.course = null;
	}

	// parameterized constructor
	Student(String stdId, String stdName, String course){
		this.stdId = stdId;
		this.stdName = stdName;
		this.course = course;
	}
}

//create class for View
class Views {
	public static class Public {
  
	}
	
	public static class Internal extends Public {
  
	}
}

输出

下一主题使用 Jackson 将布尔值序列化和反序列化为整数

Jackson JSON Views

使用 JSON Views 进行序列化

使用 JSON Views 进行反序列化

使用自定义 JSON Views 进行序列化

联系信息

关注我们

教程

面试题

在线编译器

Python

Java

.Net Framework

AI, ML and Data Science

Cloud Technology

B.Tech and MCA

Web Technology

PHP

Software Testing

Technical Interview

Java Interview

Python

Web Interview

Database Interview

B.Tech / MCA

Important Interview

Software Testing Interview

Company Interviews

Online Compilers

Multiple Choice Questions

Jackson 教程

Jackson 注解

序列化/反序列化

高级编组

Jackson JSON Views

使用 JSON Views 进行序列化

使用 JSON Views 进行反序列化

使用自定义 JSON Views 进行序列化

相关帖子

将布尔值序列化和反序列化为整数

使用 Jackson 比较 JSON 对象

序列化和反序列化枚举

反序列化为集合和数组

Jackson 日期

基于自定义标准序列化字段

Map 序列化和反序列化

订阅 Tpoint Tech

联系信息

关注我们

教程

面试题

在线编译器