jaxb解析xml为对象例子

通过jaxb方式把xml文件映射成bean对象。

1、新建java工程或者web工程都可以。
2、通过精简必须导入jar包
         activation.jar
        jaxb-api-2.0.jar
        jaxb-impl-2.0.1.jar
        jsr173_api-1.0.jar
3、 新建xml文件
    <?xml version="1.0" encoding="UTF-8"?>
    < root>

< template
   start="true"
   ip="127.0.0.1"
   port="3344"
   server="server"
/>
<template ... ... />
    </root>

4、新建bean对象，xml的映射文件。
Vo.java 如下
  

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
})
@XmlRootElement(name = "[color=red]template[/color]")
public class Vo {

	@XmlAttribute
	private String start;
	@XmlAttribute
	private String ip;
	@XmlAttribute
	private String port;
	@XmlAttribute
	private String server;
	
	
	public String getStart() {
		return start;
	}
	public void setStart(String start) {
		this.start = start;
	}
	public String getIp() {
		return ip;
	}
	public void setIp(String ip) {
		this.ip = ip;
	}
	public String getPort() {
		return port;
	}
	public void setPort(String port) {
		this.port = port;
	}
	public String getServer() {
		return server;
	}
	public void setServer(String server) {
		this.server = server;
	}
}
   

该文件对应xml文件中 循环节点 template 元素

Root.java 文件如下

import java.util.ArrayList;
import java.util.List;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
})
@XmlRootElement(name = "[color=blue]root[/color]")
public class Root {
	
	protected List<Vo> [color=red]template[/color];
	
	public List<Vo> getTemplateList() {
        if (template == null) {
        	template = new ArrayList<Vo>();
        }
        return this.template;
    }
}

注意bean对象与xml映射的关系。

5、 解析xml为bean类

public static void gernateConfig() throws Exception{
		StringBuffer buffer  = null;
		JAXBContext jaxbContext;
		try {
                           //读入xml文件流
                           InputStream is = Excecute.class.getResourceAsStream(“/conf/config.xml”);
			BufferedReader in = new BufferedReader(new InputStreamReader(is));
			buffer = new StringBuffer();
			String line = "";
			while ((line = in.readLine()) != null) {
				buffer.append(line);
			}
			
			//加载映射bean类
			jaxbContext = JAXBContext.newInstance(Root.class);
                           //创建解析
			Unmarshaller um = jaxbContext.createUnmarshaller();
			StreamSource streamSource = new StreamSource(new StringReader(buffer.toString()));
			Root root = (Root) um.unmarshal(streamSource); 
		} catch (Exception e) {
			e.printStackTrace();
			throw new Exception(e.getMessage());
		}
	}

6、 把bean对象生成xml字符串方法

public static String gernateConfigXml(Root root) throws Exception {
		if (root != null) {
			try {
				JAXBContext context = JAXBContext.newInstance(Root.class);
				Marshaller m = context.createMarshaller();
				m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
				Writer writer = new StringWriter();
				m.marshal(root, writer);
				try {
					String xml = writer.toString();
					writer.flush();
					writer.close();
					return xml;
				} catch (IOException e) {
					return "";
				}
			} catch (Exception e) {
				throw new Exception("失败!");
			}
		} else {
			return null;
		}
	}

附件为仅包含jaxb解析，反解析过程java工程代码。