(Spring MVC/Jackson)将查询参数映射到@ModelAttribute:LOWERCASE_WITH_UNDERSCORE到SNAKE_CASE失败

Question

@GetMapping("item")
public @ResponseBody String get(@ModelAttribute Item item)

Item 有属性

• name

• itemType

当我访问/item?name=foo&item_type=bar了item被只填充name 未用itemType.

我尝试了很多东西来获取itemType映射的属性item_type.

• 新增@JsonProperty( "ITEM_TYPE")里面Item的itemType属性.这里描述.
• 添加了一个JackonConfiguration,将propertyNamingStrategy设置为PropertyNamingStrategy.SNAKE_CASE.这里描述.
• 将spring.jackson.property-naming-strategy = SNAKE_CASE添加到我的Spring Boot application.properties文件中.这里描述
• 在Item类级别添加了PropertyNamingStrategy .这里描述.

我怎么解决这个问题？

顺便说一句.对于传入的不是传出的JSON序列化我只有这个问题Item.

---

更新04/24/17:

下面是一个最小的示例,用于演示问题:访问时/item您会看到"传出"的JSON序列化有效,但访问时/item/search?name=foo&item_type=bar它不适用于'传入'JSON反序列化.

项目

package sample;

import java.io.Serializable;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.PropertyNamingStrategy.SnakeCaseStrategy;
import com.fasterxml.jackson.databind.annotation.JsonNaming;

@JsonNaming(SnakeCaseStrategy.class)
public class Item implements Serializable {
    private String name;
    @JsonProperty("item_type")
    private String itemType;
    public Item() { }
    public Item(String name, String itemType) {
        this.name = name;
        this.itemType = itemType;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getItemType() {
        return itemType;
    }
    public void setItemType(String itemType) {
        this.itemType = itemType;
    }
}

ItemController.java

package sample;

import org.springframework.data.domain.Page;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/item")
public class ItemController {
    @GetMapping("search")
    public @ResponseBody Page<Item> search(@ModelAttribute Item probe) {
        System.out.println(probe.getName());
        System.out.println(probe.getItemType());
        //query repo by example item probe here...
        return null;
    }
    @GetMapping
    public Item get() {
        return new Item("name", "itemType");
    }   
}

JacksonConfiguration.java

package sample;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;

import com.fasterxml.jackson.databind.PropertyNamingStrategy;

@Configuration
public class JacksonConfiguration {
    @Bean
    public Jackson2ObjectMapperBuilder jackson2ObjectMapperBuilder() {
        return new Jackson2ObjectMapperBuilder()
                .propertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
    }
} 

SampleBootApplication.java

package sample;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SampleBootApplication {
    public static void main(String[] args) {
        SpringApplication.run(SampleBootApplication.class, args);
    }
}

application.properties

logging.level.org.springframework=INFO
spring.profiles.active=dev
spring.jackson.property-naming-strategy=SNAKE_CASE

的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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>sample</groupId>
    <artifactId>sample</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </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-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-cache</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</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-thymeleaf</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>nz.net.ultraq.thymeleaf</groupId>
                    <artifactId>thymeleaf-layout-dialect</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <!-- Spring Boot Actuator displays build-related information if a META-INF/build-info.properties 
                            file is present -->
                        <goals>
                            <goal>build-info</goal>
                        </goals>
                        <configuration>
                            <additionalProperties>
                                <encoding.source>${project.build.sourceEncoding}</encoding.source>
                                <encoding.reporting>${project.reporting.outputEncoding}</encoding.reporting>
                                <java.source>${maven.compiler.source}</java.source>
                                <java.target>${maven.compiler.target}</java.target>
                            </additionalProperties>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Answer 1

通过在没有 Spring 帮助的情况下完成 Jackson 工作来解决。

@GetMapping("search")
public @ResponseBody Page<Item> search(@RequestParam Map<String,String> params) {
    ObjectMapper mapper = new ObjectMapper();
    //Not actually necessary
    //mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
    Item probe = mapper.convertValue(params, Item.class);

    System.out.println(probe.getName());
    System.out.println(probe.getItemType());
    //query repo by example item probe here...
    return null;
}