jdk16之后com.sun.tools的替代品是什么

Question

我读了一些文章，教如何实现Lombok。它提到lombok是由JavacTrees、TreeMaker在jdk包com.sun.tools中实现的，如下所示：

import com.sun.source.tree.Tree;
import com.sun.tools.javac.api.JavacTrees;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.processing.JavacProcessingEnvironment;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.TreeTranslator;
import com.sun.tools.javac.util.*;
import javax.annotation.processing.*;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.tools.Diagnostic;
import java.util.Set;
@SupportedSourceVersion(SourceVersion.RELEASE_8)
@SupportedAnnotationTypes("com.example.lombok.MyGetter")
public class MyGetterProcessor extends AbstractProcessor {
private Messager messager;
private JavacTrees javacTrees; 
private TreeMaker treeMaker;
private Names names;
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
this.messager = processingEnv.getMessager();
this.javacTrees = JavacTrees.instance(processingEnv);
Context context = ((JavacProcessingEnvironment) processingEnv).getContext();
this.treeMaker = TreeMaker.instance(context);
this.names = Names.instance(context);
}
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
Set<? extends Element> elementsAnnotatedWith = roundEnv.getElementsAnnotatedWith(MyGetter.class);
elementsAnnotatedWith.forEach(e -> {
JCTree tree = javacTrees.getTree(e);
tree.accept(new TreeTranslator() {
@Override
public void visitClassDef(JCTree.JCClassDecl jcClassDecl) {
List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
for (JCTree jcTree : jcClassDecl.defs) {
if (jcTree.getKind().equals(Tree.Kind.VARIABLE)) {
JCTree.JCVariableDecl jcVariableDecl = (JCTree.JCVariableDecl) jcTree;
jcVariableDeclList = jcVariableDeclList.append(jcVariableDecl);
}
}
jcVariableDeclList.forEach(jcVariableDecl -> {
messager.printMessage(Diagnostic.Kind.NOTE, jcVariableDecl.getName() + " has been processed");
jcClassDecl.defs = jcClassDecl.defs.prepend(makeGetterMethodDecl(jcVariableDecl));
});
super.visitClassDef(jcClassDecl);
}
});
});
return true;
}
private JCTree.JCMethodDecl makeGetterMethodDecl(JCTree.JCVariableDecl jcVariableDecl) {
ListBuffer<JCTree.JCStatement> statements = new ListBuffer<>();
// 生成表达式 例如 this.a = a;
JCTree.JCExpressionStatement aThis = makeAssignment(treeMaker.Select(treeMaker.Ident(
names.fromString("this")), jcVariableDecl.getName()), treeMaker.Ident(jcVariableDecl.getName()));
statements.append(aThis);
JCTree.JCBlock block = treeMaker.Block(0, statements.toList());

JCTree.JCVariableDecl param = treeMaker.VarDef(treeMaker.Modifiers(Flags.PARAMETER),
jcVariableDecl.getName(), jcVariableDecl.vartype, null);
List<JCTree.JCVariableDecl> parameters = List.of(param);

JCTree.JCExpression methodType = treeMaker.Type(new Type.JCVoidType());
return treeMaker.MethodDef(treeMaker.Modifiers(Flags.PUBLIC),
getNewMethodName(jcVariableDecl.getName()), methodType, List.nil(),
parameters, List.nil(), block, null);
}
private Name getNewMethodName(Name name) {
String s = name.toString();
return names.fromString("get" + s.substring(0, 1).toUpperCase() + s.substring(1, name.length()));
}
private JCTree.JCExpressionStatement makeAssignment(JCTree.JCExpression lhs, JCTree.JCExpression rhs) {
return treeMaker.Exec(
treeMaker.Assign(
lhs,
rhs
)
);
}
}

但是，com.sun.tools在jdk 16之后无法访问。jdk 16之后是如何实现的？

我试图找到新版本Lombok的源代码，但我在github中只找到了Lombok 1.18.20以下版本的源代码。Lombok的1.18.20以下版本仍然使用com.sun.tools来实现。正如我所知，在Lombok 1.18.20之后，它使用了另一种实现。

在jdk 16之后，如果不访问com.sun.tools，我该如何做到这一点？

更新：我阅读了Lombok的新版本源代码。我看到它导入的包如下：

import com.sun.tools.javac.jvm.ClassWriter;
import com.sun.tools.javac.main.JavaCompiler;
import com.sun.tools.javac.processing.JavacFiler;
import com.sun.tools.javac.processing.JavacProcessingEnvironment;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.util.Context;

但是在jdk16之后，这些包已经不可访问了。为什么龙目仍然可以使用它们？

Answer 1

pom.xml&fo.java 模块

这两份文件会给你答案。

他在模块信息中注册了jdk.compiler

也在pom.xml 中注册

<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
<showDeprecation>true</showDeprecation>
<showWarnings>true</showWarnings> 
<fork>true</fork>
<compilerargs>
<arg>-Werror</arg>
<arg>-Xlint:all</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
<arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
</compilerargs>
</configuration>
</plugin>
</plugins>
</build>