xstream--------优雅的构造xml和解析xml

在一次调用webservice接口时，因为webservice通信的主要报文格式为xml，如果通过直接拼接字符串的方式来生成xml，则会导致代码特别混乱；并且由于字符串大量拼接也会占用JVM大量内存，我们是不是应该有一种类似于java bean转json这样子优雅的方式来讲java bean转成xml报文呢？答案是肯定的，它就是Xstream。

Xstream的官方地址为http://x-stream.github.io/index.html

Xstream的结构组件：

1. 转换器（Converters）

　　Xstream内置了大量的converters将java bean转换为xml，如JavaBeanConverter等。

2. 驱动（Drivers (Writer and Reader)）

　　实现了从流中读取xml

3. 上下文（Context）

4. 外观（Facade）

实际应用Xstream

1. 创建XstreamUtils工具类，代码如下

package com.hibase.common.utils;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.DomDriver;

/**
 * xstream工具类
 *
 * @author hufeng
 * @date 2019/07/09
 */
public class XStreamUtils {

    private XStreamUtils() {
    }

    /**
     * 通过静态内部类实现单例模式
     */
    private static class LazyHolder {
        private static final XStreamUtils INSTANCE = new XStreamUtils();
    }

    private static class SingletonXstream {

        private static XStream xStream = null;

        static {

            if (xStream == null) {

                xStream = new XStream(new DomDriver());
                // 去掉class属性
                xStream.aliasSystemAttribute(null, "class");
                //避免出现以下警告:Security framework of XStream not initialized, XStream is probably vulnerable
                XStream.setupDefaultSecurity(xStream);
            }
        }
    }

    public static XStream getInstance() {

        return SingletonXstream.xStream;
    }

    /**
     * 对象直接转换为XML字符串格式
     *
     * @param t
     * @param <T>
     * @return
     */
    public static <T> String toXml(T t) {
        XStream xstream = XStreamUtils.getInstance();
        xstream.allowTypeHierarchy(t.getClass());
        xstream.processAnnotations(t.getClass());
        return xstream.toXML(t);
    }

    /**
     * XML直接转化为对象
     *
     * @param xml
     * @param clazz
     * @param <T>
     * @return
     */
    @SuppressWarnings("unchecked")
    public static <T> T toBean(String xml, Class<T> clazz) {
        XStream xstream = XStreamUtils.getInstance();
        xstream.allowTypeHierarchy(clazz);
        xstream.processAnnotations(clazz);
        T obj = (T) xstream.fromXML(xml);
        return obj;
    }
}

2. 创建java bean，代码如下

package com.hichain.tms.api.entity.soap.request;

import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamImplicit;
import lombok.Data;
import org.hibernate.validator.constraints.NotBlank;

import java.util.List;

/**
 * OA生成账单vo
 *
 * @author hufeng
 * @date 2019/07/09
 */
@Data
@XStreamAlias("ser:setReimbursementByTms")
public class OaBillVO {

    /**
     * 工号
     */
    @NotBlank(message = "提交人不能为空")
    private String userNo;

    /**
     * 报销人工号
     */
    @NotBlank(message = "提交人不能为空")
    private String bxUserNo;

    /**
     * 请款类型
     */
    @NotBlank(message = "付款对象类型不能为空")
    private String applyType;

    /**
     * 支付公司CODE
     */
    @NotBlank(message = "付款对象类型不能为空")
    private String payCompanyId;

    /**
     * 支付对象CODE
     */
    @NotBlank(message = "付款对象不能为空")
    private String payObiectId;

    /**
     * 产品类型CODE
     */
    @NotBlank(message = "产品类型不能为空")
    private String productTypeId;

    /**
     * 费用科目CODE
     */
    @NotBlank(message = "费用科目不能为空")
    private String costSubjectsId;

    /**
     * 利润中心CODE
     */
    @NotBlank(message = "利润中心不能为空")
    private String profitCenterId;

    /**
     * 币别
     */
    @NotBlank(message = "实付币种不能为空")
    private String invoiceCurrency;

    /**
     * 发票金额
     */
    @NotBlank(message = "实付金额不能为空")
    private String invoiceAmount;

    /**
     * 事由
     */
    @NotBlank(message = "事由不能为空")
    private String cause;

    /**
     * 备注
     */
    @NotBlank(message = "备注不能为空")
    private String remarks;

    /**
     * 付款币别
     */
    @NotBlank(message = "实付币种不能为空")
    private String payCurrency;

    /**
     * 付款金额
     */
    @NotBlank(message = "实付金额不能为空")
    private String payAmount;

    /**
     * 冲借款对象
     */
    @XStreamImplicit(itemFieldName = "offsetLoan")
    private List<OaBillRushedVO> oaBillRushedVOs;
}

测试main代码

package com.hichain.tms.utils;

import com.hibase.common.utils.XStreamUtils;
import com.hichain.tms.api.entity.soap.request.OaBillRushedVO;
import com.hichain.tms.api.entity.soap.request.OaBillVO;

import java.util.Arrays;
import java.util.List;

/**
 * 发送OA soap工具类
 *
 * @author hufeng
 * @date 2019/07/09
 */
public class Test {

    private Test() {

    }

    /**
     * 生成OA SOAP报文
     *
     * @param oaBillVO
     * @return
     */
    public static String buildSoapMessage(OaBillVO oaBillVO) {

        return XStreamUtils.toXml(oaBillVO);
    }

    public static void main(String[] args) {

        OaBillVO oaBillVOArg0 = new OaBillVO();

        oaBillVOArg0.setPayObiectId("12313");
        oaBillVOArg0.setApplyType("12313");

        OaBillRushedVO oaBillRushedVO = new OaBillRushedVO();

        oaBillRushedVO.setLoanNo("123");
        oaBillRushedVO.setOffsetAmount("123.23");

        OaBillRushedVO oaBillRushedVO1 = new OaBillRushedVO();

        oaBillRushedVO1.setLoanNo("234");
        oaBillRushedVO1.setOffsetAmount("234.23");

        List<OaBillRushedVO> billRushedVOS = Arrays.asList(oaBillRushedVO, oaBillRushedVO1);

        oaBillVOArg0.setOaBillRushedVOs(billRushedVOS);

        System.out.println(buildSoapMessage(oaBillVOArg0));
    }
}