模仿mongodb採用xml+json實現小型資料庫

mini-mongodb

   模仿mongodb採用Xml+json實現小型資料庫;    1.實現資料庫建立    2.表的建立    3.表資料的增、刪、改、查    供大家參考學習使用，有助於更好的瞭解MongoDB的實現原理！

代碼： http://zhangdaiscott.github.io/mini-mogodb

   package org.jeecgframework;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.UUID;import org.jdom.Document;import org.jdom.Element;import org.jdom.JDOMException;import org.jdom.input.SAXBuilder;import org.jdom.output.XMLOutputter;import com.google.gson.Gson;public class MiniMogodb {private static final String _uuid = "_uuid";/** * 擷取表的全部資料 *  * @param path * @param tablename * @return * @throws Exception */public List loadTableDatas(String path, String tablename) throws Exception {Gson gson = new Gson();FileInputStream file = new FileInputStream(path);SAXBuilder saxBuilder = new SAXBuilder();Document document = saxBuilder.build(file);Element root = document.getRootElement();List l = new ArrayList();List list = root.getChildren();for (Element x : list) {if (x.getAttributeValue("name").equals(tablename)) {List al = x.getChildren();for (Element s : al) {String data = s.getText();if (data == null) {break;}Map mp = gson.fromJson(data, Map.class);l.add(mp);}}}return l;}/** * 表插入資料 *  * @param path * @param tablename * @param po * @return * @throws JDOMException * @throws IOException */public boolean addData(String path, String tablename, Object po)throws JDOMException, IOException {Gson gson = new Gson();boolean flag = false;FileInputStream file = new FileInputStream(path);SAXBuilder saxBuilder = new SAXBuilder();Document document = saxBuilder.build(file);Element root = document.getRootElement();List list = root.getChildren();for (Element x : list) {if (x.getAttributeValue("name").equals(tablename)) {Map base = new HashMap();base.put(_uuid, UUID.randomUUID().toString());Element data = new Element("data");String json = gson.toJson(po);Map mp = gson.fromJson(json, Map.class);base.putAll(mp);data.addContent(gson.toJson(base));x.addContent(data);}}XMLOutputter out = new XMLOutputter();out.output(document, new FileOutputStream(path));flag = true;System.out.println("----------insert --- data --- success----------------------");return flag;}/** * 表修改資料 *  * @param path * @param tablename * @param po * @throws JDOMException * @throws IOException */public void updateData(String path, String tablename, Object po)throws JDOMException, IOException {FileInputStream file = new FileInputStream(path);SAXBuilder saxBuilder = new SAXBuilder();Document document = saxBuilder.build(file);Element root = document.getRootElement();Gson gson = new Gson();List list = root.getChildren();for (Element x : list) {if (x.getAttributeValue("name").equals(tablename)) {List al = x.getChildren();for (Element s : al) {// 如果定位Data[通過UUID唯一標示]Map mp = gson.fromJson(s.getText(), Map.class);Map newmp = gson.fromJson(gson.toJson(po), Map.class);if (mp.get(_uuid).equals(newmp.get(_uuid))) {mp.putAll(newmp);Element data = new Element("data");data.setText(gson.toJson(mp));x.removeContent(s);x.addContent(data);break;}}}}XMLOutputter out = new XMLOutputter();out.output(document, new FileOutputStream(path));System.out.println("----------update --- data --- success----------------------");}/** * 表刪除資料 *  * @param path * @param tablename * @param po * @throws JDOMException * @throws IOException */public void deleteData(String path, String tablename, Object po)throws JDOMException, IOException {FileInputStream file = new FileInputStream(path);Gson gson = new Gson();SAXBuilder saxBuilder = new SAXBuilder();Document document = saxBuilder.build(file);Element root = document.getRootElement();List list = root.getChildren();for (Element x : list) {List al = x.getChildren();if (x.getAttributeValue("name").equals(tablename)) {for (Element s : al) {// 如果定位Data[通過UUID唯一標示]Map mp = gson.fromJson(s.getText(), Map.class);Map newmp = gson.fromJson(gson.toJson(po), Map.class);if (mp.get(_uuid).equals(newmp.get(_uuid))) {x.removeContent(s);break;}}}}XMLOutputter out = new XMLOutputter();out.output(document, new FileOutputStream(path));System.out.println("----------delete --- data --- success----------------------");}/** * 建立資料庫 *  * @param path * @throws Exception */public void createDataBase(String path) throws Exception {FileOutputStream file1 = new FileOutputStream(path);Document document = new Document();Element root = new Element("database");Element sort1 = new Element("table");sort1.setAttribute("name", "test");Element sort2 = new Element("table");sort2.setAttribute("name", "system.indexs");Element sort3 = new Element("table");sort3.setAttribute("name", "system.users");root.addContent(sort1);root.addContent(sort2);root.addContent(sort3);document.setRootElement(root);XMLOutputter out = new XMLOutputter();out.output(document, file1);System.out.println("----------create---database---success-------------------");}}

{"sex":"男","age":20.0,"name":"lisan","money":2000.98,"_uuid":"a2b64d1a-63ea-4a1b-b1e3-67adcc687c0a"}
  
  
  

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