xstream--------優雅的構造xml和解析xml

在一次調用webservice接口時，因為webservice通信的主要報文格式為xml，如果通過直接拼接字符串的方式來生成xml，則會導致代碼特別混亂；並且由於字符串大量拼接也會占用JVM大量內存，我們是不是應該有一種類似於java bean轉json這樣子優雅的方式來講java bean轉成xml報文呢？答案是肯定的，它就是Xstream。

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

Xstream的結構組件：

1. 轉換器（Converters）

　　Xstream內置了大量的converters將java bean轉換為xml，如JavaBeanConverter等。

2. 驅動（Drivers (Writer and Reader)）

　　實現了從流中讀取xml

3. 上下文（Context）

4. 外觀（Facade）

實際應用Xstream

1. 創建XstreamUtils工具類，代碼如下

package com.hibase.common.utils;

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

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

    private XStreamUtils() {
    }

    /**
     * 通過靜態內部類實現單例模式
     */
    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屬性
                xStream.aliasSystemAttribute(null, "class");
                //避免出現以下警告:Security framework of XStream not initialized, XStream is probably vulnerable
                XStream.setupDefaultSecurity(xStream);
            }
        }
    }

    public static XStream getInstance() {

        return SingletonXstream.xStream;
    }

    /**
     * 對象直接轉換為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直接轉化為對象
     *
     * @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. 創建java bean，代碼如下

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

    /**
     * 工號
     */
    @NotBlank(message = "提交人不能為空")
    private String userNo;

    /**
     * 報銷人工號
     */
    @NotBlank(message = "提交人不能為空")
    private String bxUserNo;

    /**
     * 請款類型
     */
    @NotBlank(message = "付款對象類型不能為空")
    private String applyType;

    /**
     * 支付公司CODE
     */
    @NotBlank(message = "付款對象類型不能為空")
    private String payCompanyId;

    /**
     * 支付對象CODE
     */
    @NotBlank(message = "付款對象不能為空")
    private String payObiectId;

    /**
     * 產品類型CODE
     */
    @NotBlank(message = "產品類型不能為空")
    private String productTypeId;

    /**
     * 費用科目CODE
     */
    @NotBlank(message = "費用科目不能為空")
    private String costSubjectsId;

    /**
     * 利潤中心CODE
     */
    @NotBlank(message = "利潤中心不能為空")
    private String profitCenterId;

    /**
     * 幣別
     */
    @NotBlank(message = "實付幣種不能為空")
    private String invoiceCurrency;

    /**
     * 發票金額
     */
    @NotBlank(message = "實付金額不能為空")
    private String invoiceAmount;

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

    /**
     * 備注
     */
    @NotBlank(message = "備注不能為空")
    private String remarks;

    /**
     * 付款幣別
     */
    @NotBlank(message = "實付幣種不能為空")
    private String payCurrency;

    /**
     * 付款金額
     */
    @NotBlank(message = "實付金額不能為空")
    private String payAmount;

    /**
     * 沖借款對象
     */
    @XStreamImplicit(itemFieldName = "offsetLoan")
    private List<OaBillRushedVO> oaBillRushedVOs;
}

測試main代碼

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;

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

    private Test() {

    }

    /**
     * 生成OA SOAP報文
     *
     * @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));
    }
}