从Java对象实例生成XSD的框架

Question

I need some framework to create xsd from java object.
i know jaxb and xstream but those frameworks is not what i need, because those framework generate from java class XSD, but i need to generate from values of instance of java XSD.
for example:

My java class:

public class Example {

   public List<String> elements;

}

Insert value Yo the Object:

public class Main {
   public static void main(final String[] args) throws Exception {

        Example e = new Example();

        e.elements,add("a"); 

        e.elements,add("b");

        e.elements,add("c");

        // Now i want to generate e.elements to xsd file like example below.


    }
}

This is my expected xsd:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://www.w3schools.com"
xmlns="http://www.w3schools.com"
elementFormDefault="qualified">

<xs:element name="something">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="a" type="xs:string"/>
      <xs:element name="b" type="xs:string"/>
      <xs:element name="c" type="xs:string"/>
     </xs:sequence>
  </xs:complexType>
</xs:element>

Answer 1

What you need is not XJC, but a different JAXB tool namely schemagen. It's usage is pretty straightforward and clearly explained here .

And as an example, I tried the following:

Example.java

@XmlType(namespace = Namespaces.SOME_NAMESPACE,
     propOrder = {"a", "b", "c"})
@XmlAccessorType(XmlAccessType.FIELD)
public class Example {

    @XmlElement(required = true, defaultValue = "requiredElementValue")
    private String a;

    @XmlAttribute(required = true)
    private String b;

    @XmlAttribute(required = false)
    private String c;

}

Relevant portion of pom.xml

    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>jaxb2-maven-plugin</artifactId>
            <version>1.5</version>
            <executions>
                <execution>
                    <id>schemagen</id>
                    <goals>
                        <goal>schemagen</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <transformSchemas>
                    <transformSchema>
                        <uri>http://some/namespace</uri>
                        <toPrefix>some</toPrefix>
                        <toFile>myschema.xsd</toFile>
                    </transformSchema>
                </transformSchemas>
                <includes>
                    <include>**/*.java</include>
                </includes>
            </configuration>
        </plugin>   
    </plugins>

And the output -> myschema.xsd

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<xs:schema version="1.0" targetNamespace="http://some/namespace" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:complexType name="example">
    <xs:sequence>
      <xs:element name="a" type="xs:string" default="requiredElementValue"/>
    </xs:sequence>
    <xs:attribute name="b" type="xs:string" use="required"/>
    <xs:attribute name="c" type="xs:string"/>
  </xs:complexType>
</xs:schema>

Answer 2

You can do it with Maven tool using jaxb2:xjc plugin

Simple example

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>jaxb2-maven-plugin</artifactId>
    <version>1.5</version>
    <executions>
        <execution>
            <id>schema1-xjc</id>
            <goals>
                <goal>xjc</goal>
            </goals>
            <configuration>
                <schemaFiles>schema1.xsd</schemaFiles>
                <packageName>com.example.foo</packageName>
                <staleFile>${project.build.directory}/jaxb2/.schema1XjcStaleFlag</staleFile>
            </configuration>
        </execution>
    </executions>
</plugin>  

Plugin usage