数据格式转换，数据解析，实体类、json、map、xml

       在做项目时，自己的系统经常需要与别的系统交互，实质上是数据的交互，这就牵涉到数据格式的转换，本篇总结一下常用的几种数据格式转换，主要有实体类与json、map、xml格式的相互转换。

       1、json与实体类互相转换

        工具类：     

package cn.usi.zhjt.pay.util;import java.io.IOException;import org.codehaus.jackson.map.ObjectMapper;import org.json.JSONException;import org.json.JSONObject;/** * 实体类和JSON对象之间相互转化 * 依赖包jackson-all-1.7.6.jar、jsoup-1.5.2.jar */ public class JSONUtil {    /**     * 将json转化为实体POJO     * @param jsonStr     * @param obj     * @return     */    public static<T> Object JSONToObj(String jsonStr,Class<T> obj) {        T t = null;        try {            ObjectMapper objectMapper = new ObjectMapper();            t = objectMapper.readValue(jsonStr,                    obj);        } catch (Exception e) {            e.printStackTrace();        }        return t;    }         /**     * 将实体POJO转化为JSON     * @param obj     * @return     * @throws JSONException     * @throws IOException     */    public static<T> JSONObject objectToJson(T obj) throws JSONException, IOException {        ObjectMapper mapper = new ObjectMapper();          // Convert object to JSON string          String jsonStr = "";        try {             jsonStr =  mapper.writeValueAsString(obj);        } catch (IOException e) {            throw e;        }        return new JSONObject(jsonStr);    }     }

       demo：

       json转换为实体类

   //respContent，json格式参数；ResContentQyWap，json格式参数对应的实体类   ResContentQyWap resContentQy = (ResContentQyWap)JSONUtil.JSONToObj(respContent, ResContentQyWap.class);

      实体类转换成json格式字符串：

   //bean to json   ReqContentQy reqContentQy = new ReqContentQy();   //reqContentQy为实体类，可通过set等把信息放入实体类，JSONObject是net.sf.json.JSONObject   JSONObject object = JSONObject.fromObject(reqContentQy);   String request=object.toString();

      2、实体类与map相互转换

      工具类：

package com.ustcsoft.framework.util;import java.beans.BeanInfo;import java.beans.IntrospectionException;import java.beans.Introspector;import java.beans.PropertyDescriptor;import java.lang.reflect.InvocationTargetException;import java.util.HashMap;import java.util.Map;import org.apache.commons.beanutils.PropertyUtilsBean;public class MapConvertUtil {/** * 将JavaBean实体类转为map类型，然后返回一个map类型的值 * @param obj，要转化的JavaBean 对象  * @return 需要返回的map */    public static Map<String, Object> beanToMap(Object obj) {         Map<String, Object> params = new HashMap<String, Object>(0);         try {             PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();             PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(obj);             for (int i = 0; i < descriptors.length; i++) {                 String name = descriptors[i].getName();                 if (!"class".equals(name)) {                 if(propertyUtilsBean.getNestedProperty(obj, name) != null){                params.put(name, propertyUtilsBean.getNestedProperty(obj, name));                }                }             }         } catch (Exception e) {             e.printStackTrace();         }         return params;     }        /**      * 将一个 Map 对象转化为一个 JavaBean      * @param clazz 要转化的类型      * @param map 包含属性值的 map      * @return 转化出来的 JavaBean 对象     * @throws IntrospectionException     * @throws IllegalAccessException     * @throws InstantiationException     * @throws InvocationTargetException     */      public static <T> T mapToBean(Class<T> clazz, Map<?, ?> map) {          T obj = null;          try {              BeanInfo beanInfo = Introspector.getBeanInfo(clazz);              obj = clazz.newInstance(); // 创建 JavaBean 对象                // 给 JavaBean 对象的属性赋值              PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();              for (int i = 0; i < propertyDescriptors.length; i++) {                  PropertyDescriptor descriptor = propertyDescriptors[i];                  String propertyName = descriptor.getName();                  if (map.containsKey(propertyName)) {                      // 下面一句可以 try 起来，这样当一个属性赋值失败的时候就不会影响其他属性赋值。                      Object value = map.get(propertyName);                      if ("".equals(value)) {                          value = null;                      }                      Object[] args = new Object[1];                      args[0] = value;                      try {                          descriptor.getWriteMethod().invoke(obj, args);                      } catch (InvocationTargetException e) {                          System.out.println("字段映射失败");                      }                  }              }          } catch (IllegalAccessException e) {              System.out.println("实例化 JavaBean 失败");          } catch (IntrospectionException e) {              System.out.println("分析类属性失败");          } catch (IllegalArgumentException e) {              System.out.println("映射错误");          } catch (InstantiationException e) {              System.out.println("实例化 JavaBean 失败");          }          return (T) obj;      }}

      demo:      

        OnlineSigningInfo onlineSign = new OnlineSigningInfo();                //onlineSign，实体类。requestMap，转化后的map格式参数        Map<String, Object> requestMap = MapConvertUtil.beanToMap(onlineSign);                //OnlineSigningInfo.class，要转化的类型 。requestMap，需要转换的map格式数据        onlineSign= MapConvertUtil.mapToBean(OnlineSigningInfo.class, requestMap); 

       3、实体类与xml格式数据

        工具类;

package cn.usi.zhjt.pay.util;import java.io.IOException;import java.io.StringReader;import java.io.StringWriter;import java.lang.reflect.Field;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import javax.xml.transform.TransformerException;import org.w3c.dom.Document;import org.w3c.dom.Node;import org.w3c.dom.NodeList;import org.xml.sax.InputSource;import org.xml.sax.SAXException;import com.sun.org.apache.xml.internal.serialize.OutputFormat;import com.sun.org.apache.xml.internal.serialize.XMLSerializer;import com.sun.org.apache.xpath.internal.XPathAPI;public class XMLConverUtil {/** * 遍历list，扩展子节点 * @param sb，原有stringbuffer数据 * @param list，需要转换的list格式数据 * @throws Exception */public static void getStringByList(StringBuffer sb, List list)throws Exception {if (list != null && list.size() != 0) {for (Object o : list) {sb.append("<");//根据自己的需要给自己的list设立节点名称sb.append("MyList");sb.append(">");//根据list内的数据，扩展子节点getStringProperty(sb, o);sb.append("</");sb.append("MyList");sb.append(">");}}}/** * 将字段key与值value，拼接成"<key>value</key>"形式 * key可为String、Integer、int，此三种类型数据形成的对象和List * @param sb * @param vo * @throws Exception */private static void getStringProperty(StringBuffer sb, Object vo)throws Exception {for (Field field : vo.getClass().getDeclaredFields()) {field.setAccessible(true);Object obj = field.get(vo);if (obj != null) {sb.append("<");sb.append(field.getName());sb.append(">");//根据字段的数据格式类型处理数据if ("java.util.List".equals(field.getType().getName())) {//处理list类型数据，扩展子节点getStringByList(sb, (List) obj);} else if ("java.lang.String".equals(field.getType().getName())|| "java.lang.Integer".equals(field.getType().getName())|| "int".equals(field.getType().getName())) {//String、Integer包装类和int型数据，直接设值sb.append(obj);} else {getStringProperty(sb, obj);}sb.append("</");sb.append(field.getName());sb.append(">");}}}private static DocumentBuilder getDocumentBuilder()throws ParserConfigurationException {DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();return dbf.newDocumentBuilder();}public static Document getDocument(InputSource inputSource)throws SAXException, IOException, ParserConfigurationException {return getDocumentBuilder().parse(inputSource);}/** * 将String类型数据转换为Document类型对象 * @param text * @return * @throws SAXException * @throws IOException * @throws ParserConfigurationException */public static Document getDOMByString(String text) throws SAXException,IOException, ParserConfigurationException {InputSource in = new InputSource(new StringReader(text));return getDocument(in);}public static Node string2Node(String xmlstr) throws SAXException,IOException, ParserConfigurationException {Document doc = string2Dom(xmlstr);return doc.getDocumentElement();}public static String dom2String(Document doc) throws IOException {doc.normalize();StringWriter wr = new StringWriter();OutputFormat of = new OutputFormat();of.setOmitXMLDeclaration(true);of.setIndenting(false);of.setPreserveSpace(true);XMLSerializer ser = new XMLSerializer(of);ser.setOutputCharStream(wr);ser.serialize(doc);return wr.toString();}public static Document string2Dom(String xml) throws SAXException,IOException, ParserConfigurationException {return getDOMByString(xml);}public static NodeList getNodes(Node doc, String xpath)throws TransformerException {return XPathAPI.selectNodeList(doc, xpath);}public static Node getSingleNode(Node doc, String xpath)throws TransformerException {return XPathAPI.selectSingleNode(doc, xpath);}public static Node createElement(Document doc, String name, String value) {Node element = doc.createElement(name);if (value != null)setNodeValue(element, value, true);return element;}public static void setNodeValue(Node node, String value)throws TransformerException {if (node == null) {return;}Node textNode = getSingleNode(node, "./text()");if (textNode != null) {textNode.setNodeValue(value);} else {textNode = node.getOwnerDocument().createTextNode(value);node.appendChild(textNode);}}public static void setNodeValue(Node node, String value, boolean replace) {if (node == null) {return;}Node textNode = node.getOwnerDocument().createTextNode(value);node.appendChild(textNode);}/** * Object转XML * xml里的根元素，根据自己的需要自己设置，编码格式也是 * 子元素，从实体类里获取属性名和属性值写入 * @param vo，需要转换的实体类 * @return String，字符串 * @throws Exception */public static String getStringByObject(Object vo) throws Exception {StringBuffer sb = new StringBuffer();sb.append("<?xml version=\"1.0\" encoding=\"gb2312\"?>");//根据自己的需要设置根节点sb.append("<RequestContent>");getStringProperty(sb, vo);sb.append("</RequestContent>");return sb.toString();}/** * XML转Object * @param inputXML，需要转换的xml格式数据 * @param object，需要转换成的实体类型 * @return 返回需要格式的实体类对象 * @throws Exception */public static <T> T getObjectByString(String inputXML,Object object) throws Exception {//将String类型转换为Document类型对象Document doc = getDOMByString(inputXML);//获取第一个节点下面的所以子节点NodeList list = doc.getFirstChild().getChildNodes();Map<String, String> map = new HashMap<String, String>();//遍历节点，将Document对象转换成mapfor (int k = 0; k < list.getLength(); k++) {map.put(list.item(k).getNodeName().toUpperCase(), list.item(k).getTextContent());}for (Field field : object.getClass().getDeclaredFields()) {field.setAccessible(true);field.set(object,map.get(field.getName().toUpperCase()));}return (T)object;}}

           demo:

                ReqContent4001 reqContent4001 = new ReqContent4001();reqContent4001.setAddress("安徽合肥高新区");//通过set等设值//bean转换为xml格式数据String requestContentXml =XMLDomUtil.getStringByObject(reqContent4001);//xml格式数据转换为beanReqContent4001 result4001 = getObjectByString(requestContentXml, ReqContent4001.class);

          以上，实现了实体类与json、map、xml格式的相互转换。