找不到适合 GeoJsonPoint 类型的构造函数

Question

很难弄清楚我做错了什么。可悲的是，我曾经让它工作过，但无法确定是什么改变了它。

据我了解，现在应该完全支持。

有问题的对象：

@Document
public class Place {

    public final static String URI = "/place";

    @Id private String id;

    private String name;

    private String caption;

    private GeoJsonPoint location;

    public Place() {}

    public Place(GeoJsonPoint geoJsonPoint) {
        this.location = geoJsonPoint;
    }

    // Proper getters & setters clipped.
}

调用（我的 Spring Boot 版本由于某种原因包含了额外的 x/y 坐标。）

{
    "id": null,
    "name": null,
    "caption": null,
    "location": {
        "x": 41.988161,
        "y": -87.6911499,
        "type": "Point",
        "coordinates": [
            41.988161,
            -87.6911499
        ]
    }
}

Pom（也许我有错误/冲突的依赖关系？）

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>...</groupId>
    <artifactId>...</artifactId>
    <version>0.1.0</version>

    <properties>
        <start-class>com.nestorledon.hang2gether.core.Application</start-class>

        <!-- Includes new GeoJson support. -->
        <spring-data-releasetrain.version>Fowler-RELEASE</spring-data-releasetrain.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.0.M2</version>
    </parent>

    <dependencies>

        <dependency>
            <groupId>org.springframework.hateoas</groupId>
            <artifactId>spring-hateoas</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.security.oauth</groupId>
            <artifactId>spring-security-oauth2</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test-mvc</artifactId>
            <version>1.0.0.M2</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-mongodb</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-rest-webmvc</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin> 
                <artifactId>maven-compiler-plugin</artifactId> 
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>

        <repository>
            <id>spring-milestone</id>
            <url>https://repo.spring.io/libs-milestone</url>
            <snapshots><enabled>true</enabled></snapshots>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots><enabled>true</enabled></snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>

Answer 1

终于搞定了。

创建了一个自定义的 JsonDeserializer

public class GeoJsonDeserializer extends JsonDeserializer<GeoJsonPoint> {

    private final static String GEOJSON_TYPE_POINT = "Point";

    private final static String JSON_KEY_GEOJSON_TYPE = "type";
    private final static String JSON_KEY_GEOJSON_COORDS = "coordinates";


    @Override
    public GeoJsonPoint deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {

        final JsonNode tree = jp.getCodec().readTree(jp);
        final String type = tree.get(JSON_KEY_GEOJSON_TYPE).asText();
        final JsonNode coordsNode = tree.get(JSON_KEY_GEOJSON_COORDS);

        double x = 0;
        double y = 0;
        if(GEOJSON_TYPE_POINT.equalsIgnoreCase(type)) {
            x = coordsNode.get(0).asDouble();
            y = coordsNode.get(1).asDouble();
        }

        else {
            System.out.println(String.format("No logic present to deserialize %s ", tree.asText()));
        }

        final GeoJsonPoint point = new GeoJsonPoint(x, y);

        return point;
    }
}

然后我只是在属性本身上指定了 a 转换器。

@JsonDeserialize(using = GeoJsonDeserializer.class)
private GeoJsonPoint location;

Answer 2

GeoJsonModule 像魅力一样工作 :)

mapper.registerModule(new GeoJsonModule());

Answer 3

Spring Data MongoDB 已经包含一个可以在jackson中注册的模块来反序列化GeoJsonPoint。

要安装（在 Spring Boot 中），只需添加到您的配置类： @Bean public Module registerGeoJsonModule(){ return new GeoJsonModule(); }

那么你应该可以使用反序列化：

{
    "location":{
        "x":0,
        "y":0
    }
}

Answer 4

像这样你可以注册任何自定义的ObjectMapper:

@Configuration
public class HttpMessageConvertersConfig implements WebMvcConfigurer {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        ObjectMapper objectMapper = Jackson2ObjectMapperBuilder.json()
                .modules(new JavaTimeModule(), new Jdk8Module(), new GeoJsonModule())
                .build();
        converters.add(new MappingJackson2HttpMessageConverter(objectMapper));
    }

}

Answer 5

把它放在@Configuration 类中

@Bean
public GeoJsonModule geoJsonModule() {
    return new GeoJsonModule();
}