Spring OXM-XStream注解

概述

XStream不但可以通过编程的方式对XML进行转换，而且支持基于注解的方式。

我们先来看下支持的注解

注解 说明 作用目标 @XStreamAlias 别名注解 类、字段 @XStreamAsAttribute 转换成属性 字段 @XStreamOmitField 忽略字段 字段 @XstreamConverter 注入转换器 对象 @XstreamImplicit 隐式集合 集合字段

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示例

package com.xgj.oxm.xstream.quickDemo.annotation;import java.util.ArrayList;import java.util.Date;import java.util.List;import java.util.Map;import com.thoughtworks.xstream.annotations.XStreamAlias;import com.thoughtworks.xstream.annotations.XStreamAsAttribute;import com.thoughtworks.xstream.annotations.XStreamConverter;import com.thoughtworks.xstream.annotations.XStreamImplicit;/** *  *  * @ClassName: User *  * @Description: 使用注解 *  * @author: Mr.Yang *  * @date: 2017年12月6日 下午9:17:11 */@XStreamAlias("user")public class User {    @XStreamAsAttribute    @XStreamAlias("userId")    private int id;    @XStreamAlias("userName")    private String userName;    @XStreamAlias("password")    private String password;    @XStreamAlias("credits")    private int credits;    @XStreamAlias("lastIp")    private String lastIp;    @XStreamConverter(DateConverter.class)    private Date lastVisit;    @XStreamImplicit    private List<LoginLog> logs;    private Map datas;    public List<LoginLog> getLogs() {        return logs;    }    public void setLogs(List logs) {        this.logs = logs;    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getUserName() {        return userName;    }    public void setUserName(String userName) {        this.userName = userName;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public int getCredits() {        return credits;    }    public void setCredits(int credits) {        this.credits = credits;    }    public String getLastIp() {        return lastIp;    }    public void setLastIp(String lastIp) {        this.lastIp = lastIp;    }    public Date getLastVisit() {        return lastVisit;    }    public void setLastVisit(Date lastVisit) {        this.lastVisit = lastVisit;    }    public void addLoginLog(LoginLog log) {        if (this.logs == null) {            logs = new ArrayList<LoginLog>();        }        logs.add(log);    }    public Map getDatas() {        return datas;    }    public void setDatas(Map datas) {        this.datas = datas;    }}

package com.xgj.oxm.xstream.quickDemo.annotation;import java.io.Serializable;import java.util.Date;import com.thoughtworks.xstream.annotations.XStreamAlias;import com.thoughtworks.xstream.annotations.XStreamAsAttribute;import com.thoughtworks.xstream.annotations.XStreamConverter;@XStreamAlias("loginLog")public class LoginLog implements Serializable {    private static final long serialVersionUID = 1L;    @XStreamAsAttribute    @XStreamAlias("id")    private int loginLogId;    @XStreamAsAttribute    private int userId;    @XStreamAlias("ip")    private String ip;    @XStreamAlias("loginDate")    @XStreamConverter(DateConverter.class)    private Date loginDate;    public int getLoginLogId() {        return loginLogId;    }    public void setLoginLogId(int loginLogId) {        this.loginLogId = loginLogId;    }    public int getUserId() {        return userId;    }    public void setUserId(int userId) {        this.userId = userId;    }    public String getIp() {        return ip;    }    public void setIp(String ip) {        this.ip = ip;    }    public Date getLoginDate() {        return loginDate;    }    public void setLoginDate(Date loginDate) {        this.loginDate = loginDate;    }}

解读

通过 @XStreamAlias为别名注解，一般用于目标类或者字段，比如 @XStreamAlias(“user”) @XStreamAlias(“userId”)

@XstreamConverter注解用于注入自定义的转换器，比如@XStreamConverter(DateConverter.class)注入一个日期转换器

对于集合类型，可以用@XStreamImplicit注解来隐藏，作用和Stream#addImplicitCollection方法一样。

@XStreamAsAttribute注解将Java对象映射为XML元素的一个属性

@XStreamOmitField注解标注的Java对象将不会出现在XML中。

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自定义转换器

package com.xgj.oxm.xstream.quickDemo.annotation;import java.text.SimpleDateFormat;import java.util.Date;import com.thoughtworks.xstream.converters.SingleValueConverter;public class DateConverter implements SingleValueConverter {    public DateConverter() {       }      public String toString(Object obj) {        try {            SimpleDateFormat dateFormat = new SimpleDateFormat(                    "yyyy-MM-dd HH:mm:ss");            dateFormat.setLenient(true);            return dateFormat.format(((Date)obj));        } catch (Exception e) {            return null;        }    }    public Object fromString(String date) {        try {            SimpleDateFormat dateFormat = new SimpleDateFormat(                    "yyyy-MM-dd HH:mm:ss");            dateFormat.setLenient(true);            return dateFormat.parse(date);        } catch (Exception e) {            return null;        }    }    public boolean canConvert(Class type) {        return type.equals(Date.class);    }}

测试类

package com.xgj.oxm.xstream.quickDemo.annotation;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.nio.charset.Charset;import java.util.Date;import com.thoughtworks.xstream.XStream;public class Test {    private static XStream xstream;    static {        xstream = new XStream();        // (1) 第一张方式 手工注册 ： 实现该方法，判断要转换的类型        // xstream.processAnnotations(User.class);        // xstream.processAnnotations(LoginLog.class);        // (2) 第二种方法 自动检测 自动加载注解Bean 推荐        xstream.autodetectAnnotations(true);    }    // 初始化转换对象    public static User getUser() {        LoginLog log1 = new LoginLog();        LoginLog log2 = new LoginLog();        log1.setIp("192.168.1.91");        log1.setLoginDate(new Date());        log2.setIp("127.0.0.1");        log2.setLoginDate(new Date());        User user = new User();        user.setId(1);        user.setUserName("xstream");        user.addLoginLog(log1);        user.addLoginLog(log2);        return user;    }    /**     * JAVA对象转化为XML     */    public static void objectToXml() throws Exception {        User user = getUser();        FileOutputStream fs = new FileOutputStream(                "D://XStreamAnnotationSample.xml");        OutputStreamWriter writer = new OutputStreamWriter(fs,                Charset.forName("UTF-8"));        xstream.toXML(user, writer);        System.out.println("output xml:\n" + xstream.toXML(user));    }    /**     * XML转化为JAVA对象     */    public static User xmlToObject() throws Exception {        FileInputStream fis = new FileInputStream(                "D://XStreamAnnotationSample.xml");        InputStreamReader reader = new InputStreamReader(fis,                Charset.forName("UTF-8"));        User user = (User) xstream.fromXML(fis);        for (LoginLog log : user.getLogs()) {            if (log != null) {                System.out.println("访问IP: " + log.getIp());                System.out.println("访问时间: " + log.getLoginDate());            }        }        return user;    }    public static void main(String[] args) throws Exception {        objectToXml();        xmlToObject();    }}

解读

要启用XStream提供的注解功能，需要在执行对象和XML转换之前注册标注了XStream注解的Java对象。 比如

xstream.processAnnotations(User.class);xstream.processAnnotations(LoginLog.class);

手工注册User和LoginLog对象。

XStream除了手工注册外，还提供了一个自动检测标注了XStream注解的java对象的方法Xstream#autodetectAnnotations(true),不仅方便，而且提供了缓存机制缓存所有标注了XStream注解的Java对象。

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运行结果

output xml:<user userId="1">  <userName>xstream</userName>  <credits>0</credits>  <loginLog id="0" userId="0">    <ip>192.168.1.91</ip>    <loginDate>2017-12-07 21:57:52</loginDate>  </loginLog>  <loginLog id="0" userId="0">    <ip>127.0.0.1</ip>    <loginDate>2017-12-07 21:57:52</loginDate>  </loginLog></user>Security framework of XStream not initialized, XStream is probably vulnerable.访问IP: 192.168.1.91访问时间: Thu Dec 07 21:57:52 CST 2017访问IP: 127.0.0.1访问时间: Thu Dec 07 21:57:52 CST 2017

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示例源码

代码已托管到Github—> https://github.com/yangshangwei/SpringMaster