OpenRewrite教程：精准修改特定方法参数上的注解属性

type: specs.openrewrite.org/v1beta/recipe
name: org.example.MandatoryRequestParameter
displayName: Make Spring `RequestParam` mandatory
description: Add `required` attribute to `RequestParam` and set the value to `true`.
recipeList:
  - org.openrewrite.java.AddOrUpdateAnnotationAttribute:
      annotationType: org.springframework.web.bind.annotation.RequestParam
      attributeName: required
      attributeValue: "true"

<plugin>
  <groupId>org.openrewrite.maven</groupId>
  <artifactId>rewrite-maven-plugin</artifactId>
  <version>4.38.0</version> <!-- 请使用最新版本 -->
  <configuration>
    <activeRecipes>
      <recipe>org.example.MandatoryRequestParameter</recipe>
    </activeRecipes>
  </configuration>
</plugin>

import org.openrewrite.ExecutionContext;
import org.openrewrite.Recipe;
import org.openrewrite.TreeVisitor;
import org.openrewrite.java.AddOrUpdateAnnotationAttribute;
import org.openrewrite.java.JavaIsoVisitor;
import org.openrewrite.java.JavaVisitor;
import org.openrewrite.java.UsesType;
import org.openrewrite.java.tree.J;
import org.openrewrite.java.tree.JavaType;
import org.openrewrite.java.tree.TypeUtils;
import org.jetbrains.annotations.NotNull;

import java.util.List;

public class MandatoryRequestParameter extends Recipe {

    private static final String REQUEST_PARAM_FQ_NAME = "org.springframework.web.bind.annotation.RequestParam";
    private static final String NOT_NULL_FQ_NAME = "javax.validation.constraints.NotNull"; // 引入NotNull注解的完全限定名

    @Override
    public @NotNull String getDisplayName() {
        return "使Spring `RequestParam`注解强制必填";
    }

    @Override
    public String getDescription() {
        return "为满足特定条件的 `RequestParam` 注解添加 `required=true` 属性。";
    }

    @Override
    protected TreeVisitor<?, ExecutionContext> getSingleSourceApplicableTest() {
        // 优化：只有当源文件包含 RequestParam 注解时，才运行此Visitor。
        return new UsesType<>(REQUEST_PARAM_FQ_NAME);
    }

    @Override
    protected @NotNull JavaVisitor<ExecutionContext> getVisitor() {
        // 创建一个用于添加或更新注解属性的内部Visitor实例
        JavaIsoVisitor<ExecutionContext> addAttributeVisitor = new AddOrUpdateAnnotationAttribute(
                REQUEST_PARAM_FQ_NAME, "required", "true", false
        ).getVisitor();

        return new JavaIsoVisitor<ExecutionContext>() {
            @Override
            public J.Annotation visitAnnotation(J.Annotation annotation, ExecutionContext ctx) {
                J.Annotation a = super.visitAnnotation(annotation, ctx);

                // 1. 检查当前访问的注解是否为 @RequestParam
                if (!TypeUtils.isOfClassType(a.getType(), REQUEST_PARAM_FQ_NAME)) {
                    return a;
                }

                // 2. 使用 Cursor 向上导航到父节点，获取参数声明
                // 当我们访问一个注解时，它的父节点通常是 J.VariableDeclarations (参数声明)
                J.VariableDeclarations variableDeclaration = getCursor().getParent().getValue();

                // 3. 定义条件：
                //    a. 检查参数是否带有 @NotNull 注解
                boolean hasNotNull = variableDeclaration.getLeadingAnnotations().stream()
                        .anyMatch(ann -> TypeUtils.isOfClassType(ann.getType(), NOT_NULL_FQ_NAME));

                //    b. 检查参数类型是否为 java.lang.Number 的子类型
                JavaType paramType = variableDeclaration.getType();
                boolean isNumberType = TypeUtils.isAssignableTo("java.lang.Number", paramType);

                //    c. 检查参数名称是否为 "fred"
                String paramName = variableDeclaration.getVariables().get(0).getSimpleName();
                boolean isFredParam = paramName.equals("fred");

                // 4. 应用条件逻辑：如果满足任何一个条件，则委托给 addAttributeVisitor 进行修改
                if (hasNotNull || isNumberType || isFredParam) {
                    // 将当前的注解 'a' 及其 Cursor 传递给 addAttributeVisitor 进行处理
                    // 这是确保子Visitor在正确上下文执行的关键
                    return (J.Annotation) addAttributeVisitor.visit(a, ctx, getCursor());
                }
                return a;
            }
        };
    }
}

import org.springframework.web.bind.annotation.RequestParam;
import javax.validation.constraints.NotNull;

class ControllerClass {
    public String sayHello (
        @NotNull @RequestParam(value = "name") String name, // 满足 @NotNull 条件
        @RequestParam(value = "lang") String lang,           // 不满足条件
        @RequestParam(value = "aNumber") Long aNumber,      // 满足 Number 类型条件
        @RequestParam(value = "fred") String fred           // 满足名称为 "fred" 条件
    ) {
       return "Hello";
    }
}

import org.springframework.web.bind.annotation.RequestParam;
import javax.validation.constraints.NotNull;

class ControllerClass {
    public String sayHello (
        @NotNull @RequestParam(required = true, value = "name") String name,
        @RequestParam(value = "lang") String lang,
        @RequestParam(required = true, value = "aNumber") Long aNumber,
        @RequestParam(required = true, value = "fred") String fred
    ) {
       return "Hello";
    }
}

import org.junit.jupiter.api.Test;
import org.openrewrite.java.JavaParser;
import org.openrewrite.test.RecipeSpec;
import org.openrewrite.test.RewriteTest;

import static org.openrewrite.java.Assertions.java;

class MandatoryRequestParameterTest implements RewriteTest {

    @Override
    public void defaults(RecipeSpec spec) {
        spec.recipe(new MandatoryRequestParameter())
            .parser(JavaParser.fromJavaVersion().classpath("spring-web", "validation-api")); // 确保classpath包含必要的依赖
    }

    @Test
    void requiredRequestParam() {
        rewriteRun(
            java(
                """
                  import org.springframework.web.bind.annotation.RequestParam;
                  import javax.validation.constraints.NotNull;

                  class ControllerClass {
                    public String sayHello (
                      @NotNull @RequestParam(value = "name") String name,
                      @RequestParam(value = "lang") String lang,
                      @RequestParam(value = "aNumber") Long aNumber,
                      @RequestParam(value = "fred") String fred
                    ) {
                      return "Hello";
                    }
                  }
                """,
                """
                  import org.springframework.web.bind.annotation.RequestParam;
                  import javax.validation.constraints.NotNull;

                  class ControllerClass {
                    public String sayHello (
                      @NotNull @RequestParam(required = true, value = "name") String name,
                      @RequestParam(value = "lang") String lang,
                      @RequestParam(required = true, value = "aNumber") Long aNumber,
                      @RequestParam(required = true, value = "fred") String fred
                    ) {
                      return "Hello";
                    }
                  }
                """
            )
        );
    }
}