Generating XML Schema from JAXB class files in Ant

Is it p开发者_运维知识库ossible to use the shemagen ant Task to generate an xsd schema from class files instead of from source?

You could probably write something fairly easily, and then call it from Ant:

import java.io.File;
import java.io.IOException;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.SchemaOutputResolver;
import javax.xml.transform.Result;
import javax.xml.transform.stream.StreamResult;

public class SchemaGenerator {

    public static void main(String[] args) throws Exception {
        String contextPath = args[0];
        String outputDir = args[1];
        JAXBContext jc = JAXBContext.newInstance(contextPath);
        jc.generateSchema(new MySchemaOutputResolver(schemaFileName));
    }

    private static class MySchemaOutputResolver extends SchemaOutputResolver {

        private String outputDir;

        public MySchemaOutputResolver(String outputDir) {
            this.outputDir = outputDir;
        }

        public Result createOutput(String namespaceURI, String suggestedFileName) throws IOException {
            File file = new File(outputDir + "/" + suggestedFileName);
            StreamResult result = new StreamResult(file);
            result.setSystemId(file.toURI().toURL().toString());
            return result;
        }

    }   

}

In your context path you would need a jaxb.index file with a list of classes to be included in your JAXBContext. Or you could pass the class names to the SchemaGenerator class and load them via a ClassLoader.