当xsd与minoccurs = 0和nillable = true时创建JAXB元素

Question

我的xsd有两个用minouucrs = 0和nillable = true定义的字段。当我为此生成Java对象时，它生成JAXBElement而不是普通字符串。有任何解决方法可以避免JAXBElement。

JAXBElement<String> userId,
JAXBElement<String> userType.


**testSchema.xsd**
        <xs:complexType name="testSchema">
                <xs:sequence>
                    <xs:element minOccurs="0" name="name" type="xs:int" />
                    <xs:element minOccurs="0" name="age" type="xs:int" />
                    <xs:element minOccurs="0" name="userId" nillable="true"
                        type="xs:string" />
                    <xs:element minOccurs="0" name="usertype" nillable="true"
                        type="xs:string" />
                </xs:sequence>
            </xs:complexType>

Why it's not creating normal XMLElement instaed of creating XMLElementRef?

I am using below dependency and plugin.

pom Dependencies

<dependencies>
                <dependency>
                    <groupId>javax.xml.bind</groupId>
                    <artifactId>jaxb-api</artifactId>
                    <version>2.1</version>
                    <scope>provided</scope>
                </dependency>
                <dependency>
                    <groupId>com.sun.xml.bind</groupId>
                    <artifactId>jaxb-impl</artifactId>
                    <version>2.2.2</version>
                    <scope>provided</scope>
                </dependency>
                <dependency>
                    <groupId>org.apache.ws.commons.schema</groupId>
                    <artifactId>XmlSchema</artifactId>
                    <version>1.4.5</version>
                    <scope>provided</scope>
                </dependency>
            </dependencies>

        <build>
            <plugins>

                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>${java.source.version}</source>
                        <target>${java.target.version}</target>
                    </configuration>
                </plugin>

                <plugin>
                    <groupId>org.jvnet.jaxb2.maven2</groupId>
                    <artifactId>maven-jaxb2-plugin</artifactId>
                    <version>0.13.1</version>

                    <executions>
                        <execution>
                            <id>schema1-generate</id>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                            <configuration>
                                <schemaDirectory>src/main/resources/schema/testschema</schemaDirectory>
                                <generateDirectory>src/main/java</generateDirectory>
                                <schemaIncludes>
                                    <include>**/*.wsdl</include>
                                    <include>*.wsdl</include>
                                </schemaIncludes>
                                <generateDirectory>src/main/java</generateDirectory>
                            </configuration>
                        </execution>
                    </executions>
                </plugin>
                </plugins>
        </build>

我也在src / main / resources

下定义了bindings.xjb

<jaxb:bindings version="2.0"
               xmlns:jxb="http://java.sun.com/xml/ns/jaxb"
               xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <jaxb:bindings schemaLocation="/schema/testschema/*.xsd"
                   node="/xs:schema">
        <jaxb:globalBindings generateElementProperty="false"/>
    </jaxb:bindings>

为什么它为这两个字段生成JAXBElement而不是普通的String。