Errai :: codeGen :: GWT framework: code generation tutorial in the Java class library
Errai :: codeGen :: GWT framework: code generation tutorial in the Java class library
Errai :: CodeGen is a Java library for Google Web Toolkit (GWT), which provides a simple and powerful way to generate code.This tutorial will introduce how to use Errai :: CodeGen to generate code and provide some examples for reference.
1. Introduce dependencies
First, introduce ERRAI :: codegen dependencies in your project.You can add the following dependencies to Maven or Gradle files:
Maven dependence:
<dependency>
<groupId>org.jboss.errai</groupId>
<artifactId>errai-codegen</artifactId>
<version>3.2.0.Final</version>
</dependency>
Gradle dependencies:
groovy
dependencies {
compile 'org.jboss.errai:errai-codegen:3.2.0.Final'
}
2. Create a class
Create a class to generate code in your Java code.You can use the annotations and API provided by Errai :: CodeGen to define the code generation rules.
Example code:
import org.jboss.errai.codegen.DefModifiers;
import org.jboss.errai.codegen.TemporaryVariable;
import org.jboss.errai.codegen.meta.MetaClassFactory;
import org.jboss.errai.codegen.util.Refs;
import org.jboss.errai.codegen.util.Stmt;
import org.jboss.errai.common.metadata.RebindUtils;
public class CodeGenerator {
public static void main(String[] args) {
// Generate a class called "HelloWorld"
String packageName = "com.example";
String className = "HelloWorld";
ClassStructureBuilder<?> classBuilder = ClassBuilder.define(packageName, className)
.publicScope()
.body();
// Add a public static method
MethodBuild method = classBuilder.publicMethod(RebindUtils.getMethodSignature(Method.class))
.modifiers(DefModifiers.buildStatic())
.returnType(String.class);
// Method to generate code inside the body
BlockBuilder<?> blockBuilder = method.body();
// Generate a line of printing sentences
blockBuilder.append(Stmt.nestedCall(Stmt.nestedCall(Stmt.staticInvoke(System.class, "out"), "println")
.invokeStaticMethod(ClassName.class, "getMessage", Stmt.load("Hello, World!"))));
// Return a string
blockBuilder.returnValue(Stmt.loadLiteral("Hello, World!"));
// Close method and class builder
method.finish();
classBuilder.finish();
}
}
3. Generate code
In the `Main` method, call the` codegenrator.main () `to generate the code.
Example code:
public class MainClass {
public static void main(String[] args) {
CodeGenerator.main(args);
}
}
4. Run code
Run the following command compile and run code in the project root directory:
shell
mvn compile
mvn exec:java -Dexec.mainClass="com.example.MainClass"
You will see the output results in the controllers: "Hello, World!"
This is a simple errai :: codegen code generation tutorial.You can customize the code generated according to your needs.I hope this tutorial can help you understand how to use Errai :: codegen to generate code in the Java library.
Please note that the class and method names in the example code are for reference only, and you can change according to your needs.
Reference link:
- [Errai :: codeGen sentence 档]
