Spring 3.0 OXM - Spring 3.0 框架新特性

什么是OXM？

   OXM是Object-to-XML-Mapping的缩写，它是一个O/M-mapper，将java对象映射成XML数据，或者将XML数据映射成java对象。它类似 XML-Marshalling 或者是 XML-Serialization，并不是什么新技术。目前Spring framework 3.0引入了该特性。

   现在让我们看看Spring的承诺：

• 易于配置
• 一致的接口
• 一致的异常层次结构

    听起来很不错，因为没有喜欢杂乱的接口，繁琐的配置，现在就让我们来检验一下Spring OXM的设计思想，本文着重讲述OXM特性的使用方法。

 

OXM in Spring 3.0

    我们以一个Maven2实例工程来进行说明。首先，创建一个pom.xml文件：

<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.unitedcoders.examples</groupId>
    <artifactId>SpringOxmExample</artifactId>
    <packaging>jar</packaging>
    <version>1.0.0-SNAPSHOT</version>
    <name>SpringOxmExample</name>
    <url>http://united-coders.com</url>
    <build>
        <finalName>SpringOxmExample</finalName>
        <plugins>
            <!-- Compiler Plugin to compile on Java 1.6 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <compilerVersion>1.6</compilerVersion>
                    <fork>true</fork>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
 
    <!-- Properties -->
    <properties>
        <spring-version>3.0.0.RELEASE</spring-version>
    </properties>
 
    <!-- Dependencies -->
    <dependencies>
        <!-- Spring framework -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-oxm</artifactId>
            <version>${spring-version}</version>
        </dependency>
 
        <!-- Castor Xml -->
        <dependency>
            <groupId>org.codehaus.castor</groupId>
            <artifactId>castor</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>xerces</groupId>
            <artifactId>xercesImpl</artifactId>
            <version>2.9.1</version>
        </dependency>
 
        <!-- Logging -->
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>
 
        <!-- Test dependencies -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.4</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

 

    该实例中我用到了三个spring 模块,spring-core,spring-beans以及spring-oxm。另外，我使用Castor工程和Apache Xerces作为XML-Marshalling-dependencies.

   

    接着，创建一个简单的javabean，将被序列换成XML字符串：

package com.unitedcoders.examples.spring.oxm.beans;
 
public class Person {
 
    private String firstname;
    
    private String lastname;
    
    private boolean developer;
 
    public String getFirstname() {
        return firstname;
    }
 
    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }
 
    public String getLastname() {
        return lastname;
    }
 
    public void setLastname(String lastname) {
        this.lastname = lastname;
    }
 
    public boolean isDeveloper() {
        return developer;
    }
 
    public void setDeveloper(boolean developer) {
        this.developer = developer;
    } 
    
}

   

    然后，为O/X-Mapper创建一个接口：

package com.unitedcoders.examples.spring.oxm.mapper;
 
import java.io.IOException;
 
public interface OxMapper {
 
    /**
     * Serializes assigned Object into a file with the assigned name.
     * 
     * @param object
     *            - Object that should be serialized
     * @param filename
     *            - name of the XML-file
     * @throws IOException
     */
    public abstract void writeObjectToXml(Object object, String filename) throws IOException;
 
    /**
     * Deserializes an object from the assigned file.
     * 
     * @param filename
     *            - name of the file that should be deserialized
     * @return deserialized object
     * @throws IOException
     */
    public abstract Object readObjectFromXml(String filename) throws IOException;
 
}

     我定义了两个方法，一个将对象转化成xml文件，一个将xml文件转换成对象。以下是该接口的实现类：

package com.unitedcoders.examples.spring.oxm.mapper;
 
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
 
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
 
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.oxm.Marshaller;
import org.springframework.oxm.Unmarshaller;
import org.springframework.oxm.XmlMappingException;
 
public class OxMapperImpl implements OxMapper {
 
    private static final Log LOG = LogFactory.getLog(OxMapperImpl.class);
 
    private Marshaller marshaller;
 
    private Unmarshaller unmarshaller;
 
    public void writeObjectToXml(Object object, String filename) throws IOException {
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(filename);
            marshaller.marshal(object, new StreamResult(fos));
        } catch (XmlMappingException e) {
            LOG.error("Xml-Serialization failed due to an XmlMappingException.", e);
        } catch (IOException e) {
            LOG.error("Xml-Serialization failed due to an IOException.", e);
        } finally {
            if (fos != null) {
                fos.close();
            }
        }
    }
 
    public Object readObjectFromXml(String filename) throws IOException {
        FileInputStream fis = null;
        try {
            fis = new FileInputStream(filename);
            return unmarshaller.unmarshal(new StreamSource(fis));
        } catch (IOException e) {
            LOG.error("Xml-Deserialization failed due to an IOException.", e);
        } finally {
            if (fis != null) {
                fis.close();
            }
        }
        return null;
    }
 
    public Marshaller getMarshaller() {
        return marshaller;
    }
 
    public void setMarshaller(Marshaller marshaller) {
        this.marshaller = marshaller;
    }
 
    public Unmarshaller getUnmarshaller() {
        return unmarshaller;
    }
 
    public void setUnmarshaller(Unmarshaller unmarshaller) {
        this.unmarshaller = unmarshaller;
    }
    
}

     待续。。。