xml格式报文的拼装，和解析成实体类

         我们的微信支付，使用的是第三方的支付，某银行的微信支持渠道。所有的接口请求、应答都是xml格式报文，这样就需要用到xml格式报文的拼装和解析，这儿简单讲一下。

        拼接xml格式报文。

        从页面表单提交和配置文件中读取出参数，或用实体类接收的页面传来的参数。建立map对象，用put()方法把参数添加进去。然后遍历map，将map转换成xml。

  StringBuffer soapResultData = new StringBuffer();
		//xml声明
		soapResultData.append("<?xml version="1.0" encoding="GBK"?><ROOT><MSG_HEAD>");
		//请求头
		soapResultData.append(requesttoxml(msgHead));
		soapResultData.append("</MSG_HEAD><MSG_BODY>");
		//请求体
		soapResultData.append(requesttoxml(resmap));
		soapResultData.append("</MSG_BODY></ROOT>");

  /**
	 * 将map转化为XML格式的字符串
	 * @param resmap
	 * @return
	 */
	public static String requesttoxml(Map<String, String> resmap){
		StringBuffer soapResultData = new StringBuffer();
		for(String key : resmap.keySet()){
			soapResultData.append("<");
			soapResultData.append(key);
			soapResultData.append(">");
			soapResultData.append(resmap.get(key));
			soapResultData.append("</");
			soapResultData.append(key);
			soapResultData.append(">");
		}
		return soapResultData.toString();
	}

        将接收到的xml格式报文，转换成实体类。

        

package com.ustcsoft.business.model;
 
import java.io.Serializable;
 
import org.apache.commons.digester3.annotations.rules.BeanPropertySetter;
import org.apache.commons.digester3.annotations.rules.ObjectCreate;
 
@ObjectCreate(pattern = "ROOT/MSG_HEAD")
public class ResponseMsgHead implements Serializable {
	/**
	 * 
	 */
	private static final long serialVersionUID = -2793215313546940251L;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/TRAN_CODE")
	private String TRAN_CODE;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/PARTNER_CODE")
	private String PARTNER_CODE;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/REQUEST_SERIAL")
	private String REQUEST_SERIAL;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/RESPONSE_DATE")
	private String RESPONSE_DATE;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/RESPONSE_TIMESTAMP")
	private String RESPONSE_TIMESTAMP;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/RESULT_CODE")
	private String RESULT_CODE;
	@BeanPropertySetter(pattern = "ROOT/MSG_HEAD/RESULT_MESSAGE")
	private String RESULT_MESSAGE;
	//get set 省略，不贴在这儿，自己使用时别忘了生成个set和get方法
}

import static org.apache.commons.digester3.binder.DigesterLoader.newLoader;
 
import java.io.StringReader;
import java.text.SimpleDateFormat;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
 
import org.apache.commons.digester3.Digester;
import org.apache.commons.digester3.annotations.FromAnnotationsRuleModule;
import org.apache.log4j.Logger;
 
import com.ustcsoft.business.model.CreditPayResponseBody;;
import com.ustcsoft.business.model.ResponseMsgHead;
import com.ustcsoft.framework.util.HTTPUtil;
import com.ustcsoft.framework.util.XMlUtil;
 
public class PayService {
	private final Map<Class<?>, FromAnnotationsRuleModule> xmlAnnotationModule = new HashMap<Class<?>, FromAnnotationsRuleModule>();
	private static final Logger logger=Logger.getLogger(PayService.class);
	
	public PayService() {
		xmlAnnotationModule.put(ResponseMsgHead.class,
				new FromAnnotationsRuleModule() {
					@Override
					protected void configureRules() {
						bindRulesFrom(ResponseMsgHead.class);
					}
				});
		xmlAnnotationModule.put(CreditPayResponseBody.class,
				new FromAnnotationsRuleModule() {
					@Override
					protected void configureRules() {
						bindRulesFrom(CreditPayResponseBody.class);
					}
				});
	}
	
	//中间业务代码省略……
			
	public <T> T parseXml(String xml, Class<T> clazz) throws Exception {
		StringReader sr = null;
		try {
			Digester digester = newLoader(xmlAnnotationModule.get(clazz)).newDigester();
			sr = new StringReader(xml);
			T pi = digester.parse(sr);
			digester.clear();
			return pi;
		} finally {
			if (sr != null) {
				sr.close();
			}
		}
	}
}

    logger.info("统一下单接口请求报文："+requestxml);
			String resultxml = HTTPUtil.postByHttps(url, requestxml,"GBK");
			logger.info("统一下单接口返回报文："+resultxml);
			if(resultxml != null){
				resultxml = XMlUtil.xmltoUpperCase(resultxml);//将XML报文中的标签，全部转化为大写
				ResponseMsgHead head = parseXml(resultxml, ResponseMsgHead.class);
				CreditPayResponseBody body = parseXml(resultxml, CreditPayResponseBody.class);
				if (null != head) {
					if(head.getRESULT_CODE().equals("000000")){
						logger.info("下单成功");
						logger.info("返回参数：sub_mch_id="+body.getSUB_MCH_ID()+"，total_fee="+body.getTOTAL_FEE()+"，out_trade_no="+body.getOUT_TRADE_NO());
						return body;
					}else{
						logger.info("下单失败，错误码："+head.getRESULT_CODE()+"，错误信息："+head.getRESULT_MESSAGE());
					}
				}
			}

  /**
	 * 将XML报文中的标签，全部转化为大写
	 * @param xmlMessage
	 * @return
	 */
	public static String xmltoUpperCase(String xmlMessage) {
        Pattern pattern = Pattern.compile("<.+?>");
        String xml = xmlMessage.split(">")[0];
        String xml0 = xmlMessage.substring(0, xml.length()+1);
        String xml1 = xmlMessage.substring(xml.length()+1);
        StringBuilder res = new StringBuilder();
        int lastIdx = 0;
        Matcher matchr = pattern.matcher(xml1);
        while (matchr.find()) {
            String str = matchr.group();
            res.append(xml1.substring(lastIdx, matchr.start()));
            res.append(str.toUpperCase());
            lastIdx = matchr.end();
        }
        res.append(xml1.substring(lastIdx));
        String result = xml0 + res.toString();
		return result;
    }

         以上就是拼接xml格式报文和解析xml格式报文。需要注意的是，在解析xml格式报文时，由于对方返回的报文的标签有小写的，结果解析出错，所以在里面做了个处理，将标签全部转化为大写。