JAXB解析生成xml

1、简介

JAXB（Java Architecture for XML Binding) 是一个业界的标准，是一项可以根据XML Schema产生Java类的技术。JAXB 已经是jdk的组成部分，不需要另外引入jar包

2、几个核心注解

（1）@XmlRootElement(name = "response")  将Java类或枚举类型映射到XML元素。

 (2)  @XmlElement(name = "result") 将Java类的一个属性映射到与属性同名的一个XML元素。

 (3)  @XmlAttribute(name="code") 将Java类的一个属性映射到与属性同名的一个XML属性。

 (4) @XmlValue(name="result") 将Java类的一个属性映射到XML元素之间的值上（例：<result code="0">成功</result> 0的获取是（3）成功的获取是4）

3、具体实例

以一个比较复杂，并且可以涵盖大部分内容的例子（代码较多，可以直接拷贝到自己工程中使用）：

工具类

import java.io.StringReader;import java.io.StringWriter;import javax.xml.bind.JAXBContext;import javax.xml.bind.JAXBException;import javax.xml.bind.Marshaller;import javax.xml.bind.Unmarshaller;/** * jaxb工具类 */public class JaxbUtil {      // 多线程安全的Context.      private JAXBContext jaxbContext;        /**      * @param types      *            所有需要序列化的Root对象的类型.      */      public JaxbUtil(Class<?>... types) {          try {              jaxbContext = JAXBContext.newInstance(types);          } catch (JAXBException e) {              throw new RuntimeException(e);          }      }        /**      * 对象转xml     */      public String toXml(Object root, String encoding) {          try {              StringWriter writer = new StringWriter();              createMarshaller(encoding).marshal(root, writer);              return writer.toString();          } catch (JAXBException e) {              throw new RuntimeException(e);          }      }        /**      * xml转对象     */      @SuppressWarnings("unchecked")      public <T> T fromXml(String xml) {          try {              StringReader reader = new StringReader(xml);              return (T) createUnmarshaller().unmarshal(reader);          } catch (JAXBException e) {              throw new RuntimeException(e);          }      }        /**      * 创建Marshaller, 设定encoding(可为Null).      */      public Marshaller createMarshaller(String encoding) {          try {              Marshaller marshaller = jaxbContext.createMarshaller();                marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);                if (!encoding.equals("") && encoding!=null) {                  marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);              }              return marshaller;          } catch (JAXBException e) {              throw new RuntimeException(e);          }      }        /**      * 创建UnMarshaller.      */      public Unmarshaller createUnmarshaller() {          try {              return jaxbContext.createUnmarshaller();          } catch (JAXBException e) {              throw new RuntimeException(e);          }      }  }

具体对象（多个）：

import javax.xml.bind.annotation.XmlAttribute;import javax.xml.bind.annotation.XmlElement;import javax.xml.bind.annotation.XmlRootElement;import javax.xml.bind.annotation.XmlValue;/** *  * 获取组织结构xml对象 */@XmlRootElement(name = "response")public class GetOrgResponse{    Result result;        Message message;        public Result getResult()    {        return result;    }        @XmlElement(name = "result")    public void setResult(Result result)    {        this.result = result;    }        public Message getMessage()    {        return message;    }        @XmlElement(name = "message")    public void setMessage(Message message)    {        this.message = message;    }        @XmlRootElement(name = "message")    public static class Message    {        Company company;                public Company getCompany()        {            return company;        }                @XmlElement(name = "company")        public void setCompany(Company company)        {            this.company = company;        }    }        @XmlRootElement(name = "result")    public static class Result    {        String code;                String result;                public String getCode()        {            return code;        }                @XmlAttribute        public void setCode(String code)        {            this.code = code;        }                public String getResult()        {            return result;        }                @XmlValue        public void setResult(String result)        {            this.result = result;        }    }}

import java.util.List;import javax.xml.bind.annotation.XmlAttribute;import javax.xml.bind.annotation.XmlElement;import javax.xml.bind.annotation.XmlRootElement;/** * 企业信息xml对象 */@XmlRootElement(name = "company")public class Company{    String id;        String name;        String enter_id;        String ver;        String short_name;        String privacy;        List<Member> members;        List<Department> departments;        public String getId()    {        return id;    }        @XmlAttribute(name = "id")    public void setId(String id)    {        this.id = id;    }        public String getName()    {        return name;    }        @XmlAttribute(name = "name")    public void setName(String name)    {        this.name = name;    }        public String getEnter_id()    {        return enter_id;    }        @XmlAttribute(name = "enter_id")    public void setEnter_id(String enter_id)    {        this.enter_id = enter_id;    }        public String getVer()    {        return ver;    }        @XmlAttribute(name = "ver")    public void setVer(String ver)    {        this.ver = ver;    }        public String getShort_name()    {        return short_name;    }        @XmlAttribute(name = "short_name")    public void setShort_name(String short_name)    {        this.short_name = short_name;    }        public String getPrivacy()    {        return privacy;    }        @XmlAttribute(name = "privacy")    public void setPrivacy(String privacy)    {        this.privacy = privacy;    }        public List<Member> getMembers()    {        return members;    }        @XmlElement(name = "member")    public void setMembers(List<Member> members)    {        this.members = members;    }        public List<Department> getDepartments()    {        return departments;    }        @XmlElement(name = "dep")    public void setDepartments(List<Department> departments)    {        this.departments = departments;    }}

import java.util.List;import javax.xml.bind.annotation.XmlAttribute;import javax.xml.bind.annotation.XmlElement;import javax.xml.bind.annotation.XmlRootElement;/** * 部门xml对象 */@XmlRootElement(name = "dep")public class Department{    String id;        String name;        String clan_order;        List<Member> members;        List<Department> departments;        public String getId()    {        return id;    }    @XmlAttribute(name = "id")    public void setId(String id)    {        this.id = id;    }        public String getName()    {        return name;    }    @XmlAttribute(name = "name")    public void setName(String name)    {        this.name = name;    }        public String getClan_order()    {        return clan_order;    }    @XmlAttribute(name = "clan_order")    public void setClan_order(String clan_order)    {        this.clan_order = clan_order;    }        public List<Member> getMembers()    {        return members;    }    @XmlElement(name = "member")    public void setMembers(List<Member> members)    {        this.members = members;    }        public List<Department> getDepartments()    {        return departments;    }    @XmlElement(name = "dep")    public void setDepartments(List<Department> departments)    {        this.departments = departments;    }    }

import javax.xml.bind.annotation.XmlAttribute;import javax.xml.bind.annotation.XmlRootElement;/** * 组织结构中成员对象 */@XmlRootElement(name = "member")public class Member{    String name;        String nbr;        String sex;        String ext;        String sort_no;        String login_name;        String pic_url;        String headship;        public String getName()    {        return name;    }        @XmlAttribute(name = "name")    public void setName(String name)    {        this.name = name;    }        public String getNbr()    {        return nbr;    }        @XmlAttribute(name = "nbr")    public void setNbr(String nbr)    {        this.nbr = nbr;    }        public String getSex()    {        return sex;    }        @XmlAttribute(name = "sex")    public void setSex(String sex)    {        this.sex = sex;    }        public String getExt()    {        return ext;    }        @XmlAttribute(name = "ext")    public void setExt(String ext)    {        this.ext = ext;    }        public String getSort_no()    {        return sort_no;    }        @XmlAttribute(name = "sort_no")    public void setSort_no(String sort_no)    {        this.sort_no = sort_no;    }        public String getLogin_name()    {        return login_name;    }        @XmlAttribute(name = "login_name")    public void setLogin_name(String login_name)    {        this.login_name = login_name;    }        public String getPic_url()    {        return pic_url;    }        @XmlAttribute(name = "pic_url")    public void setPic_url(String pic_url)    {        this.pic_url = pic_url;    }        public String getHeadship()    {        return headship;    }        @XmlAttribute(name = "headship")    public void setHeadship(String headship)    {        this.headship = headship;    }}

测试：

public class Test{    public static void main(String[] args)        throws Exception    {        JaxbUtil resultBinder = new JaxbUtil(GetOrgResponse.class);        String xml =            "<response type='orgService' subtype='orgService' msid='sssss'>"                + "<result code='0'>成功</result>"                + "<message> <company id='312003' name='xx测试' enter_id='237525' ver='3' short_name='xx测试' privacy='0'>"                + "<member name='张三' nbr='67123675' sex='1' ext='' sort_no='100' login_name='admin' pic_url='111.png' headship=''/>"                + "<dep id='312004' name='总经办' clan_order='1'></dep>"                + "<dep id='312005' name='研发部' clan_order='2'>"                + "<member name='李四' nbr='66406993' sex='1' ext='' sort_no='100' login_name='18013399396' pic_url='222.png' headship=''/>"                + "<dep id='312012' name='研发一部' clan_order='201'></dep>"                + "<dep id='312013' name='研发二部' clan_order='202'></dep>" + "</dep></company></message></response>";                GetOrgResponse res = resultBinder.fromXml(xml);        System.out.println(res.getResult().getCode());        System.out.println(res.getResult().getResult());        System.out.println(res.getMessage().getCompany().getName());        System.out.println(res.getMessage().getCompany().getEnter_id());        System.out.println(res.getMessage().getCompany().getVer());        if (res.getMessage().getCompany().getMembers() != null)        {            for (Member member : res.getMessage().getCompany().getMembers())            {                System.out.println(member.getNbr() + "=" + member.getName() + "=" + member.getPic_url());            }        }                if (res.getMessage().getCompany().getDepartments() != null)        {            for (Department dep : res.getMessage().getCompany().getDepartments())            {                System.out.println(dep.getId() + "=" + dep.getName());            }        }                if (res.getMessage().getCompany().getMembers() != null)        {            for (Member member : res.getMessage().getCompany().getMembers())            {                System.out.println(member.getNbr() + "=" + member.getName() + "=" + member.getPic_url());            }        }    }}

代码下载地址

4、遇到的小问题（注意事项）

（1）属性节点有下划线时必须这么写@XmlAttribute(name = "parentDepId")
如果只写@XmlAttribute将获取不到带下划线属性或者节点的值


（2）如果不想要某个属性或者节点，将此属性设为null即可
在使用jaxb从bean转换为xml过程中,默认会将bean中属性为null的属性过滤掉