Background

我有一个数据类

@Data
public class Data {
    @lombok.NonNull
    private String name;
}

发送到控制器

@MessageMapping("/data")
public void handleData(@Validated Data data) throws Exception {
    if (data.getName().compareTo("Alice") == 0) {
        logger.info("Alice is here!");
    }
}

以及配置Jackson将布尔值转换为整数的Bean(True-&gt；1，False-&gt；0)

@Bean
ObjectMapper registerObjectMapper() {
    ObjectMapper mapper = new ObjectMapper();

    SimpleModule module = new SimpleModule("MyBoolSerializer");
    module.addSerializer(Boolean.class, new MyBoolSerializer());
    module.addDeserializer(Boolean.class, new MyBoolDeserializer());
    module.addSerializer(boolean.class, new MyBoolSerializer());
    module.addDeserializer(boolean.class, new MyBoolDeserializer());
    
    mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);

    return mapper;
}

当我在没有设置name参数的情况下向/data发出请求时，Jackson会将其设置为null.但是，我得到了以下异常(未包装)

org.springframework.messaging.converter.MessageConversionException: 
Could not read JSON: Cannot construct instance of `com.example.myapp.entity.Data`
(no Creators, like default constructor, exist): 
cannot deserialize from Object value (no delegate- or property-based Creator)

Attempted fix

所以我把@NoArgsConstructor加到Data上.

@Data
@NoArgsConstructor   // <<<<
public class Data {
    @lombok.NonNull
    private String name;
}

现在请求/data将得到NullPointerException.不对参数进行空判断，并且运行if-statement.

我try 对数据中的name属性使用hibernate-validator的@NotNull批注，但结果是相同的:NPE.

Question

我对@NonNull和@NotNull注释的 idea 是，它们有助于验证数据，因此我不需要在控制器中手动验证它们(判断NULL、判断范围内等).然而，它似乎只有在默认构造函数不存在的情况下才有效.这是有意义的，因为在默认构造函数中不执行空判断(没有要验证的数据...).

But then it contradicts with the exception I encountered.个

可能有帮助的信息

我启用了amqp，它有自己的MessageConverter Bean，返回一个新的Jackson2JsonMessageConverter实例.

import org.springframework.amqp.support.converter.MessageConverter;
@Bean
MessageConverter jsonMessageConverter() {
    return new Jackson2JsonMessageConverter();
}

有什么 idea 吗？

顺便说一句，标题可能有点模棱两可或具有误导性，但我真的不知道问题出在哪里.

-编辑1: Pom.xml pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.7</version>
        <relativePath />
        <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo2</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>18</java.version>
    </properties>
    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
            <version>3.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate.validator</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>8.0.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.amqp</groupId>
            <artifactId>spring-rabbit</artifactId>
            <version>2.4.7</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-reactor-netty</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>