如何为jaxb2-maven-plugin生成的类添加必填参数构造方法？

方案一：通过JAXB扩展生成指定必填参数的构造方法 #

你提到的org.jvnet.jaxb2_commons:jaxb2-value-constructor其实支持自定义必填字段，不需要强制生成全参构造。只需通过JAXB绑定文件（如bindings.xjb）配置即可：

1. 绑定文件头部引入value-constructor命名空间：

<jaxb:bindings xmlns:jaxb="http://java.sun.com/xml/ns/jaxb"
               xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
               xmlns:vc="http://jaxb2-commons.dev.java.net/value-constructor"
               jaxb:extensionBindingPrefixes="xjc vc"
               jaxb:version="2.1">

2. 针对目标类配置必填字段：

<!-- 单个类配置：指定field1、field2为构造参数 -->
<jaxb:bindings schemaLocation="your-schema.xsd" node="/xs:schema/xs:complexType[@name='YourClass']">
    <vc:value-constructor fields="field1 field2"/>
</jaxb:bindings>

<!-- 全局配置：自动识别Schema中标记为必填（minOccurs="1"且无默认值）的字段生成构造 -->
<jaxb:bindings schemaLocation="your-schema.xsd" node="/xs:schema">
    <vc:value-constructor use-optional="false"/>
</jaxb:bindings>

3. Maven插件中引入扩展依赖：

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>jaxb2-maven-plugin</artifactId>
    <version>2.5.0</version>
    <executions>
        <execution>
            <goals>
                <goal>xjc</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>org.jvnet.jaxb2_commons</groupId>
            <artifactId>jaxb2-value-constructor</artifactId>
            <version>3.0.0</version>
        </dependency>
    </dependencies>
    <configuration>
        <bindingFiles>
            <bindingFile>src/main/resources/bindings.xjb</bindingFile>
        </bindingFiles>
    </configuration>
</plugin>

方案二：添加Lombok @RequiredArgsConstructor注解 #

方式1：生成时直接注入注解 #

使用jaxb2-annotate-plugin在类生成阶段直接添加Lombok注解：

1. 绑定文件配置注解注入：

<jaxb:bindings xmlns:jaxb="http://java.sun.com/xml/ns/jaxb"
               xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
               xmlns:annox="http://annox.dev.java.net"
               jaxb:extensionBindingPrefixes="xjc annox"
               jaxb:version="2.1">

    <!-- 给单个类添加注解 -->
    <jaxb:bindings schemaLocation="your-schema.xsd" node="/xs:schema/xs:complexType[@name='YourClass']">
        <annox:annotateClass>lombok.RequiredArgsConstructor</annox:annotateClass>
    </jaxb:bindings>

    <!-- 全局给所有生成类添加注解 -->
    <jaxb:bindings schemaLocation="your-schema.xsd" node="/xs:schema">
        <annox:annotateClass>lombok.RequiredArgsConstructor</annox:annotateClass>
    </jaxb:bindings>
</jaxb:bindings>

2. Maven插件配置依赖：

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>jaxb2-maven-plugin</artifactId>
    <version>2.5.0</version>
    <executions>
        <execution>
            <goals>
                <goal>xjc</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>org.jvnet.jaxb2_commons</groupId>
            <artifactId>jaxb2-annotate-plugin</artifactId>
            <version>1.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.30</version>
        </dependency>
    </dependencies>
    <configuration>
        <bindingFiles>
            <bindingFile>src/main/resources/bindings.xjb</bindingFile>
        </bindingFiles>
    </configuration>
</plugin>

方式2：生成后批量添加注解 #

用maven-replacer-plugin在生成完成后批量替换代码添加注解：

<plugin>
    <groupId>com.google.code.maven-replacer-plugin</groupId>
    <artifactId>replacer</artifactId>
    <version>1.5.3</version>
    <executions>
        <execution>
            <phase>generate-sources</phase>
            <goals>
                <goal>replace</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <filePattern>target/generated-sources/xjc/**/*.java</filePattern>
        <replacements>
            <replacement>
                <token>public class</token>
                <value>import lombok.RequiredArgsConstructor;&#10;&#10;@RequiredArgsConstructor&#10;public class</value>
            </replacement>
        </replacements>
    </configuration>
</plugin>

若需针对特定类，可调整filePattern或使用更精准的正则匹配。

内容的提问来源于stack exchange，提问作者olimtrail