什麼是OXM?
OXM是Object-to-XML-Mapping的縮寫,它是一個O/M-mapper,將java對象映射成XML數據,或者將XML數據映射成java對象。它類似 XML-Marshalling 或者是 XML-Serialization,並不是什麼新技術。目前Spring framework 3.0引入了該特性。
現在讓我們看看Spring的承諾:
- 易於配置
- 一致的接口
- 一致的異常層次結構
聽起來很不錯,因爲沒有喜歡雜亂的接口,繁瑣的配置,現在就讓我們來檢驗一下Spring OXM的設計思想,本文着重講述OXM特性的使用方法。
OXM in Spring 3.0
我們以一個Maven2實例工程來進行說明。首先,創建一個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>${spring-version}</version>
- </dependency>
- <!-- Castor Xml -->
- <dependency>
- <groupId>org.codehaus.castor</groupId>
- <artifactId>castor</artifactId>
- <version>1.2</version>
- </dependency>
- <dependency>
- <groupId>xerces</groupId>
- <artifactId>xercesImpl</artifactId>
- <version>2.9.1</version>
- </dependency>
- <!-- Logging -->
- <dependency>
- <groupId>commons-logging</groupId>
- <artifactId>commons-logging</artifactId>
- <version>1.1.1</version>
- </dependency>
- <!-- Test dependencies -->
- <dependency>
- <groupId>junit</groupId>
- <artifactId>junit</artifactId>
- <version>4.4</version>
- <scope>test</scope>
- </dependency>
- </dependencies>
- </project>
- <project>
- <modelVersion>4.0.0</modelVersion>
- <groupId>com.unitedcoders.examples</groupId>
- <artifactId>SpringOxmExample</artifactId>
- <packaging>jar</packaging>
- <version>1.0.0-SNAPSHOT</version>
- <name>SpringOxmExample</name>
- <url>http://united-coders.com</url>
- <build>
- <finalName>SpringOxmExample</finalName>
- <plugins>
- <!-- Compiler Plugin to compile on Java 1.6 -->
- <plugin>
- <groupId>org.apache.maven.plugins</groupId>
- <artifactId>maven-compiler-plugin</artifactId>
- <configuration>
- <compilerVersion>1.6</compilerVersion>
- <fork>true</fork>
- <source>1.6</source>
- <target>1.6</target>
- </configuration>
- </plugin>
- </plugins>
- </build>
- <!-- Properties -->
- <properties>
- <spring-version>3.0.0.RELEASE</spring-version>
- </properties>
- <!-- Dependencies -->
- <dependencies>
- <!-- Spring framework -->
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-core</artifactId>
- <version>${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>
該實例中我用到了三個spring 模塊,spring-core,spring-beans以及spring-oxm。另外,我使用Castor工程和Apache Xerces作爲XML-Marshalling-dependencies.
接着,創建一個簡單的javabean,將被序列換成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;
- }
- }
- 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;
- }
- }
然後,爲O/X-Mapper創建一個接口:
- 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;
- }
- 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;
- }
我定義了兩個方法,一個將對象轉化成xml文件,一個將xml文件轉換成對象。以下是該接口的實現類:
- 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;
- }
- }
- 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;
- }
- }