笔记
近日对java对象与xml文本的相互转换有一定兴趣，于是乎在网上查看了一下相关的资料。发现了castor。
并浏览了该页面http://www.jdon.com/idea/castor.htm，但发现上面的代码有一些错漏。
自己用eclipse写了一个简单的代码如下：（主要参考了上面提到的网站的内容）
该程序是读入page.xml文件，然后转化为java对象。接着把java对象写到另外一个文件里。
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1.page.xml，要被转化为对象的页面
<?xml version="1.0" encoding="UTF-8"?><homepagecollection name="this is sample"> <!-- 对应Homepagecollection类 --> <homepagecontent id="1"> <!-- 对应Homepagecontent 类 --> <name>About Us</name> <navlink>1.jsp</navlink> <icon>images/icon.gif</icon> <description>An in-depth look at creating applications with XML.</description> </homepagecontent> <homepagecontent id="2"> <!-- 对应Homepagecontent 类 --> <name>Product|Service</name> <navlink>2.jsp</navlink> <icon>images/icon.gif</icon> <description>let's tak a look at our products.</description> </homepagecontent></homepagecollection>
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2.Homepagecontent.java，一个符合JavaBean规格的简单类
package tryForCastor;
public class Homepagecontent implements java.io.Serializable {
private static final long serialVersionUID = 3689909565688657717L;
private Integer id;
private String name;
private String navlink; private String icon;
private String description;
public Homepagecontent() { }
public Integer getId() { return id; }
public void setId(Integer id) { this.id = id; }
public String getName() { return name; }
public void setName(String name) { this.name = name; } public String getNavlink() { return navlink; }
public void setNavlink(String navlink) { this.navlink = navlink; }
public String getIcon() { return icon; }
public void setIcon(String icon) { this.icon = icon; }
public String getDescription() { return description; }
public void setDescription(String description) { this.description = description; }
}
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3.Homepagecollection.java，
package tryForCastor;
import java.util.*;
public class Homepagecollection implements java.io.Serializable {
private static final long serialVersionUID = 3545239128603309878L;
private String SiteName;
private List homepagecontents = new ArrayList();
public Homepagecollection() { }
// -- manipulate the List of Page objects public void addHomePageContent(Homepagecontent homepagecontent) { homepagecontents.add(homepagecontent); }
public List getHomepagecontents() { return homepagecontents; }
// -- manipulate the name of the address book public String getName() { return SiteName; }
public void setName(String name) { this.SiteName = name; }
}
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4.mapping.xml，映射文件，把要转化的xml文件和java类联系起来
<?xml version="1.0" encoding="UTF-8"?><mapping> <description>a map file for our new template system</description> <class name="Homepagecontent"> <map-to xml="homepagecontent"/> <field name="id" type="integer"> <bind-xml name="id" node="attribute" /> </field> <field name="name" type="string" /> <field name="navlink" type="string" /> <field name="icon" type="string" /> <field name="description" type="string" /> </class> <class name="Homepagecollection"> <map-to xml="homepagecollection"/> <field name="name" type="string"> <bind-xml name="name" node="attribute" /> </field> <field name="homepagecontents" type="Homepagecontent" collection="collection" /> </class></mapping>
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5.tryCastor.java，执行转化的类
package tryForCastor;
import java.io.FileReader;import java.io.FileWriter;import java.util.*;
import org.exolab.castor.mapping.Mapping;import org.exolab.castor.xml.Marshaller;import org.exolab.castor.xml.Unmarshaller;
/** * @author hbm * */public class tryCastor { public Mapping mapping;
public String xmlfile;
public void HomePageHandle(String mapfile, String xmlfile) throws Exception { this.xmlfile = xmlfile; try { mapping = new Mapping(); mapping.loadMapping(mapfile); //读入映射文件 } catch (Exception e) { throw new Exception(e.getMessage()); }
}
// -- page.xml中的数据读入Homepagecollection public Homepagecollection read() throws Exception { Homepagecollection homepages = null; try { Unmarshaller un = new Unmarshaller(Homepagecollection.class); // xml -> java 专用类 un.setMapping(mapping);
FileReader in = new FileReader(xmlfile); homepages = (Homepagecollection) un.unmarshal(in); //转换 in.close(); } catch (Exception e) { throw new Exception(e.getMessage()); } return homepages; }
// hbm add public FileWriter write(String outFile, Object obj) throws Exception { FileWriter out = new FileWriter(outFile); try { Marshaller mar = new Marshaller(out);// java-> xml专用类 mar.setMapping(mapping); mar.marshal(obj); } catch (Exception e) { throw new Exception(e.getMessage());//转换 } return out; }
/** * @param args */ public static void main(String[] args) { tryCastor tc = new tryCastor(); try { //从page.xml读入数据并放到对象hcollection 里 tc.HomePageHandle("mapping.xml", "page.xml"); Homepagecollection hcollection = tc.read(); List list = hcollection.getHomepagecontents(); for (Iterator iter = list.iterator(); iter.hasNext();) { Homepagecontent h = (Homepagecontent) iter.next(); System.out.println(h.getDescription()); System.out.println(h.getIcon()); System.out.println(h.getName()); System.out.println(h.getNavlink()); System.out.println(h.getName2()); System.out.println(h.getId()); System.out.println(h.getClass()); System.out.println("+++++++++++++++++++++++"); } //写到xml文本 FileWriter fw = tc.write("d.xml", hcollection); if (null != fw) { fw.close(); }
} catch (Exception e) { e.printStackTrace(); }
}
}
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小结：觉得写映射文件（mapping.xml）很麻烦，是否可以用映射来解决自动查找类字段来实现java到xml的转换？