用dom4j读写数据

   从数据库表里面读取数据并生成一个xml文件给用户下载,下面是所用到的函数,要注意设置好输出到页面的文件头,还有的就是要作为一个文件给人下载的话要    将header里面的属性设置为attachment（也就是作为附件的形式，而不是inline，inline的话会直接打开的）.

public void genXml()
        {
        logger.debug("Test=================================="+enumInfoManager.getObjectList().size());
        
        HashMap<String, Object> result = this.getDefaultMap();
        
        List<EnumInfo> list = enumInfoManager.getObjectList();
        Criterion[] criterion;
        
        Document doc=DocumentHelper.createDocument();
        Element rootElement = doc.addElement("root");
        Iterator iter = list.iterator();
                
                while(iter.hasNext())
                {
                        EnumInfo enumInfo = (EnumInfo)iter.next();
                        //EnumItem enumItem = enumItemManager.getObject(enumInfo.getId());
                        List<EnumItem> itemList = enumItemManager.getObjectList(Restrictions.eq("enumInfoId", enumInfo.getId()));
                        Element recordElement = rootElement.addElement("record");
                        
                        Element idElement = recordElement.addElement("id");
                        idElement.setText(enumInfo.getId().toString());
                        
                        Element tableNameElement = recordElement.addElement("tableName");
                        tableNameElement.setText(enumInfo.getTableName()==null?"":enumInfo.getTableName());
                        
                        Element fieldNameElement = recordElement.addElement("fieldName");
                        fieldNameElement.setText(enumInfo.getFieldName()==null?"":enumInfo.getFieldName());
                        
                        Element enumNameElement = recordElement.addElement("enumName");
                        enumNameElement.setText(enumInfo.getEnumName()==null?"":enumInfo.getEnumName());
                        
                        Element statusElement = recordElement.addElement("status");
                        statusElement.setText(enumInfo.getStatus()==null?"":enumInfo.getStatus());
                        
                        Element systemFlagElement = recordElement.addElement("systemFlag");
                        systemFlagElement.setText(enumInfo.getSystemFlag()==null?"":enumInfo.getSystemFlag());                        
                                                
                        Iterator iiter = itemList.iterator();                        
                        
                        while(iiter.hasNext())
                        {
                                EnumItem enumItem = (EnumItem)iiter.next();                
                                
                                Element itemElement = recordElement.addElement("item");
                                                                
                                Element idEle = itemElement.addElement("id");
                                idEle.setText(enumItem.getId().toString());
                                
                                Element fieldEle = itemElement.addElement("fieldValue");
                                fieldEle.setText(enumItem.getFieldValue()==null?"":enumItem.getFieldValue());
                                
                                Element displayEle = itemElement.addElement("displayValue");
                                displayEle.setText(enumItem.getDisplayValue()==null?"":enumItem.getDisplayValue());
                                
                                Element infoIdEle = itemElement.addElement("enumInfoId");
                                infoIdEle.setText(enumItem.getEnumInfoId()==null?"":enumItem.getEnumInfoId().toString());
                                
                                Element orderEle = itemElement.addElement("displayOrder");
                                orderEle.setText(enumItem.getDisplayOrder()==null?"":enumItem.getDisplayOrder().toString());
                                
                                Element statusEle = itemElement.addElement("status");
                                statusEle.setText(enumItem.getStatus()==null?"":enumItem.getStatus());
                        }
                }
                
                 try
                {
                    //Writer out=new FileWriter("c:\\enum.xml");
                                this.getResponse().setHeader("Pragma","No-cache");
                                this.getResponse().setHeader("Cache-Control","no-cache");
                                this.getResponse().setDateHeader("Expires", 0);
                                this.getResponse().addHeader("Content-disposition", "attachment" + "; filename=\"" + "enum.xml" + "\"");

                                this.getResponse().setContentType("text/xml");
                    OutputFormat format=OutputFormat.createCompactFormat();
                    format.setEncoding("UTF-8");
                    XMLWriter writer=new XMLWriter(this.getResponse().getOutputStream(),format);
                    writer.write(doc);
                    writer.close();
                    this.getResponse().flushBuffer();
                    //System.out.println("生成xml文件成功！");
                   
                }
                catch(IOException e)
                {
                    e.printStackTrace();
                    result.put(SUCCESS, false);
                    outJson(result);
                    //System.out.println("生成失败了！");
                }               
        }

    这里是解析xml文件函数，有一点要注意的就是要设置好reader的编码，一开始我用的gbk，读取的时候有错误，后来改成用gbk的编码方式就行了.

public void readXml(File file)
        {
            SAXReader reader = new SAXReader();
            reader.setEncoding("utf-8");   //这里是关键设置
            Document doc = null;
            try
            {
                    doc = reader.read(file);
                    
            }
            catch(DocumentException e)
            {
                    e.printStackTrace();
            }
            
            Element rootEle = doc.getRootElement();
            Iterator iter = rootEle.elementIterator("record");
            while(iter.hasNext())
            {
                    Element recordEle = (Element)iter.next();
                    
                    String id = recordEle.elementTextTrim("id");
                    String tableName = recordEle.elementTextTrim("tableName");
                    String fieldName = recordEle.elementTextTrim("fieldName");
                    String enumName = recordEle.elementTextTrim("enumName");
                    String status = recordEle.elementTextTrim("status");
                    String systemFlag = recordEle.elementTextTrim("systemFlag");
                    
                    System.out.println(id);
                    System.out.println(tableName);
                    System.out.println(fieldName);
                    System.out.println(enumName);
                    System.out.println(status);
                    System.out.println(systemFlag);
                    
                    Iterator iiter = recordEle.elementIterator("item");
                    
                    while(iiter.hasNext())
                    {
                            Element itemEle = (Element)iiter.next();
                            
                            String iid = itemEle.elementTextTrim("id");
                            String fieldValue = itemEle.elementTextTrim("fieldValue");
                            String displayValue = itemEle.elementTextTrim("displayValue");
                            String enumInfoId = itemEle.elementTextTrim("enumInfoId");
                            String displayOrder = itemEle.elementTextTrim("displayOrder");
                            String istatus = itemEle.elementTextTrim("status");
                            
                            System.out.println(iid);
                            System.out.println(fieldValue);
                            System.out.println(displayValue);
                            System.out.println(enumInfoId);
                            System.out.println(displayOrder);
                            System.out.println(istatus);
                    }
            }
}