javaparser试用

 

1、参考文档：http://code.google.com/p/javaparser/wiki/UsingThisParser

2、添加maven依赖：

<repository>
    <id>javaparserid>
    <name>JavaParser Repositoryname>
    <url>http://javaparser.googlecode.com/svn/maven2url>
    <snapshots>
        <enabled>falseenabled>
    snapshots>
repository>

 

<dependency>
    <groupId>com.google.code.javaparsergroupId>
    <artifactId>javaparserartifactId>
    <version>1.0.8version>
dependency>

download源代码：

svn checkout http://javaparser.googlecode.com/svn/trunk/ javaparser-read-only

3、常用API的使用

Printing the CompilationUnit to System output

public class CuPrinter {

    public static void main(String[] args) throws Exception {
        // creates an input stream for the file to be parsed
        FileInputStream in = new FileInputStream("test.java");

        CompilationUnit cu;
        try {
            // parse the file
            cu = JavaParser.parse(in);
        } finally {
            in.close();
        }

        // prints the resulting compilation unit to default system output
        System.out.println(cu.toString());
    }

Visiting class methods

public class MethodPrinter {

    public static void main(String[] args) throws Exception {
        // creates an input stream for the file to be parsed
        FileInputStream in = new FileInputStream("test.java");

        CompilationUnit cu;
        try {
            // parse the file
            cu = JavaParser.parse(in);
        } finally {
            in.close();
        }

        // visit and print the methods names
        new MethodVisitor().visit(cu, null);
    }

    /**
     * Simple visitor implementation for visiting MethodDeclaration nodes. 
     */
    private static class MethodVisitor extends VoidVisitorAdapter {

        @Override
        public void visit(MethodDeclaration n, Object arg) {
            // here you can access the attributes of the method.
            // this method will be called for all methods in this 
            // CompilationUnit, including inner class methods
            System.out.println(n.getName());
        }
    }
}

Changing methods from a class with a visitor

public class MethodChanger {

    public static void main(String[] args) throws Exception {
        // creates an input stream for the file to be parsed
        FileInputStream in = new FileInputStream("test.java");

        CompilationUnit cu;
        try {
            // parse the file
            cu = JavaParser.parse(in);
        } finally {
            in.close();
        }

        // visit and change the methods names and parameters
        new MethodChangerVisitor().visit(cu, null);

        // prints the changed compilation unit
        System.out.println(cu.toString());
    }

    /**
     * Simple visitor implementation for visiting MethodDeclaration nodes.
     */
    private static class MethodChangerVisitor extends VoidVisitorAdapter {

        @Override
        public void visit(MethodDeclaration n, Object arg) {
            // change the name of the method to upper case
            n.setName(n.getName().toUpperCase());

            // create the new parameter
            Parameter newArg = ASTHelper.createParameter(ASTHelper.INT_TYPE, "value");

            // add the parameter to the method
            ASTHelper.addParameter(n, newArg);
        }

    }
}

Changing methods from a class without a visitor

public class MethodChanger {

    public static void main(String[] args) throws Exception {
        // creates an input stream for the file to be parsed
        FileInputStream in = new FileInputStream("test.java");

        CompilationUnit cu;
        try {
            // parse the file
            cu = JavaParser.parse(in);
        } finally {
            in.close();
        }

        // change the methods names and parameters
        changeMethods(cu);

        // prints the changed compilation unit
        System.out.println(cu.toString());
    }

    private static void changeMethods(CompilationUnit cu) {
        List<TypeDeclaration> types = cu.getTypes();
        for (TypeDeclaration type : types) {
            List<BodyDeclaration> members = type.getMembers();
            for (BodyDeclaration member : members) {
                if (member instanceof MethodDeclaration) {
                    MethodDeclaration method = (MethodDeclaration) member;
                    changeMethod(method);
                }
            }
        }
    }

    private static void changeMethod(MethodDeclaration n) {
        // change the name of the method to upper case
        n.setName(n.getName().toUpperCase());

        // create the new parameter
        Parameter newArg = ASTHelper.createParameter(ASTHelper.INT_TYPE, "value");

        // add the parameter to the method
        ASTHelper.addParameter(n, newArg);
    }
}

Creating a CompilationUnit from scratch

public class ClassCreator {

    public static void main(String[] args) throws Exception {
        // creates the compilation unit
        CompilationUnit cu = createCU();

        // prints the created compilation unit
        System.out.println(cu.toString());
    }

    /**
     * creates the compilation unit
     */
    private static CompilationUnit createCU() {
        CompilationUnit cu = new CompilationUnit();
        // set the package
        cu.setPakage(new PackageDeclaration(ASTHelper.createNameExpr("java.parser.test")));

        // create the type declaration 
        ClassOrInterfaceDeclaration type = new ClassOrInterfaceDeclaration(ModifierSet.PUBLIC, false, "GeneratedClass");
        ASTHelper.addTypeDeclaration(cu, type);

        // create a method
        MethodDeclaration method = new MethodDeclaration(ModifierSet.PUBLIC, ASTHelper.VOID_TYPE, "main");
        method.setModifiers(ModifierSet.addModifier(method.getModifiers(), ModifierSet.STATIC));
        ASTHelper.addMember(type, method);

        // add a parameter to the method
        Parameter param = ASTHelper.createParameter(ASTHelper.createReferenceType("String", 0), "args");
        param.setVarArgs(true);
        ASTHelper.addParameter(method, param);

        // add a body to the method
        BlockStmt block = new BlockStmt();
        method.setBody(block);

        // add a statement do the method body
        NameExpr clazz = new NameExpr("System");
        FieldAccessExpr field = new FieldAccessExpr(clazz, "out");
        MethodCallExpr call = new MethodCallExpr(field, "println");
        ASTHelper.addArgument(call, new StringLiteralExpr("Hello World!"));
        ASTHelper.addStmt(block, call);

        return cu;
    }
}

4、结论：操作相比jdt更加的容易

 

 

转载于:https://blog.51cto.com/tianya23/617244