Spring API 返回 XML 而不是 JSON

问题描述

我有两个 Spring Boot 项目 - A（带有 API 的主要大型项目）和 B（由 A 导入的库作为pom.xml 中的一个依赖项）

项目B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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>

        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.b.root</groupId>
    <artifactId>b</artifactId>
    <version>0.0.1</version>
    <packaging>jar</packaging>
    <name>b</name>
    <description>Importable Jar</description>

    <properties>
        <java.version>11</java.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <oauth2.version>2.1.1.RELEASE</oauth2.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
                <!-- Removing dependency for the embedded Tomcat -->
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
                <!-- End -->
            </exclusions>
        </dependency>

        <!-- asynchronous loggers -->
        <dependency>
            <groupId>com.lmax</groupId>
            <artifactId>disruptor</artifactId>
            <version>3.4.2</version>
        </dependency>

        <!-- Actuator -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!-- end -->

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.skyscreamer</groupId>
                    <artifactId>jsonassert</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.security.oauth.boot</groupId>
            <artifactId>spring-security-oauth2-autoconfigure</artifactId>
            <version>${oauth2.version}</version>
        </dependency>


        <!--  docusign dependencies -->

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>javax.persistence-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.5</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.6</version>
        </dependency>
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-xml</artifactId>
            <version>2.9.8</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.1.1</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>jar</goal>
                        </goals>
                        <phase>package</phase>
                        <configuration>
                            <!--to be imported on other projects-->
                            <classifier>b-classifier</classifier>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.5</version>
                <configuration>
                    <skipTests>false</skipTests>
                    <testFailureIgnore>true</testFailureIgnore>
                    <forkMode>once</forkMode>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <forceJavacCompilerUse>true</forceJavacCompilerUse>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/test/java</directory>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

</project>

项目A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 https://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.a.root</groupId>
    <artifactId>a</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>a</name>
    <description>Project A</description>

    <properties>
        <java.version>11</java.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <!-- Springboot -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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-actuator</artifactId>
        </dependency>

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

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

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

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

        <!-- JUnit -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- Postgresql -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
            <scope>provided</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.5</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.openapitools/jackson-databind-nullable -->
        <dependency>
            <groupId>org.openapitools</groupId>
            <artifactId>jackson-databind-nullable</artifactId>
            <version>0.2.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/ch.qos.logback.contrib/logback-json-classic -->
        <dependency>
            <groupId>ch.qos.logback.contrib</groupId>
            <artifactId>logback-json-classic</artifactId>
            <version>0.1.5</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/ch.qos.logback.contrib/logback-jackson -->
        <dependency>
            <groupId>ch.qos.logback.contrib</groupId>
            <artifactId>logback-jackson</artifactId>
            <version>0.1.5</version>
        </dependency>

        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.7</version>
        </dependency>

        <dependency>
            <groupId>org.everit.json</groupId>
            <artifactId>org.everit.json.schema</artifactId>
            <version>1.3.0</version>
        </dependency>

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>1.3.1.Final</version>
        </dependency>

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>1.3.1.Final</version>
        </dependency>

        <dependency>
            <groupId>com.nimbusds</groupId>
            <artifactId>nimbus-jose-jwt</artifactId>
            <version>9.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.passay</groupId>
            <artifactId>passay</artifactId>
            <version>1.6.0</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- Importing library b -->
        <dependency>
            <groupId>com.b.root</groupId>
            <artifactId>b</artifactId>
            <version>0.0.1</version>
            <classifier>b-classifier</classifier>
        </dependency>

    </dependencies>

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

</project>

项目 A 中有返回 JSON 对象的 API。但是在集成测试中，它们以 XML 格式返回数据，导致它们失败。并且只有在 A 中使用库 B 时才会发生这种情况。如果我们从 A 中删除 B，则所有测试都通过。

这是错误信息：

org.json.JSONException: Unparsable JSON string: <ResponseDTO>.....</ResponseDTO>

我的猜测是两个项目的依赖项存在某种冲突。但无法准确指出哪个依赖项。

我的猜测是，由于 spring 使用 jackson 将返回的对象转换为 json 并且项目 B 中存在依赖项，因此它可能与此库特别相关：

    <dependency>
        <groupId>com.fasterxml.jackson.dataformat</groupId>
        <artifactId>jackson-dataformat-xml</artifactId>
        <version>2.9.8</version>
    </dependency>

但我无法理解这会如何影响任何事情。如果需要更多信息，请告诉我。

编辑 1： 为控制器添加代码：

TestDTO.java

@Data // lombok annotation
public class TestDTO {

  @JsonProperty(value = "id")
  @JsonSetter(nulls = Nulls.AS_EMPTY)
  private String id;

  @JsonProperty(value = "name")
  @JsonSetter(nulls = Nulls.AS_EMPTY)
  private String name;

}

TestController.java

@RestController
public class TestController {

  @Autowired
  private final TestService testService;

  @GetMapping("/test/:id")
  public TestDTO get(@PathVariable String id) {
    return testService.get(id);
  }

}

**EDIT 2: ** 添加了请求响应头

请求

  HTTP Method = GET
  Request URI = /test/1
   Parameters = {}
      Headers = [Content-Type:"application/json",Content-Length:"616"]
         Body = <no character encoding set>
Session Attrs = {}

       Status = 200
Error message = null
      Headers = [Content-Type:"application/xml;charset=UTF-8"]
 Content type = application/xml;charset=UTF-8
         Body = <TestDTO>...</TestDTO>

解决方法

可能是，因为 Spring Boot 通过依赖项 B 获取 xml 解析库。

我会在您的映射中定义生产属性，或者配置一个 WebMvcConfigurer 以将 json 设置为默认类型。

为此，请在某处添加 WebMvcConfigurer。即使依赖 B 应该没问题，如果它在同一个 Spring 上下文中运行。这是针对 Spring Boot 2.4.2 的：

@Bean
public WebMvcConfigurer customConfigurer() {
    return new WebMvcConfigurer() {
        @Override
        public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
            configurer.defaultContentType(MediaType.APPLICATION_JSON);
        }
    };
}

jackson jackson jackson jackson-dataformat-xml java java spring spring spring-boot