java,poi 实现数据追加功能

package cn.com.excel; import org.apache.commons.io.FileUtils; import org.apache.commons.lang3.StringUtils; import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.CellStyle; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.ss.usermodel.Sheet; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.lang.reflect.Field; import java.lang.reflect.Method; import java.nio.channels.FileChannel; import java.nio.channels.FileLock; import java.util.*; import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.CellStyle; import org.apache.poi.ss.usermodel.Comment; import org.apache.poi.ss.usermodel.Font; import org.apache.poi.ss.usermodel.IndexedColors; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.ss.usermodel.Sheet; import org.apache.poi.ss.usermodel.Workbook; import org.apache.poi.ss.util.CellRangeAddress; import org.apache.poi.xssf.usermodel.XSSFClientAnchor; import org.apache.poi.xssf.usermodel.XSSFRichTextString; public abstract class ChatExcel<T> { private Class<?> clazz; public XSSFWorkbook wb; public Sheet sheet; private FileInputStream fileInput=null; private FileChannel fileChannel=null; private FileLock fileLock=null; /** * 路径是否是文件 */ public boolean isFile=false; /** * 当前行号 */ public int rownum; private List<String> headerList=new ArrayList<String>(); private int headnum=0; /** * 样式列表 */ private Map<String, CellStyle> styles; private String filePath; /** * 注解列表（Object[]{ ExcelField, Field/Method }） */ List<Object[]> annotationList = new ArrayList<>(); public ChatExcel(String filePath) { this(filePath, "聊天记录",1); } //检测文件大小。 private File checkFilePath(String filePath) { try { File file=new File(filePath); if(!file.exists()){ return file; }else{ //如果文件超出自定义的大小，新建文件 long fileSize=file.length(); if(fileSize > 1328427){//1.26MB左右，大概4-5万行左右 // 自定义的文件名称 // String fileName=DateUtils.formatDate(new Date(), "yyyyMMdd")+"-"+file.getName(); String fileName="2017"; File path=new File(file.getParent()); FileUtils.copyFile(file, new File(path,fileName)); file.delete(); } return file; } } catch (Exception e) { e.printStackTrace(); } return null; } public ChatExcel(String filePath,String title,int headnum) { File file=checkFilePath(filePath); try { clazz=Reflections.getClassGenricType(getClass()); if(file.exists() && file.isFile()){//文件存在//追加 isFile=true; fileInput= new FileInputStream(file); // fileChannel=new RandomAccessFile(file, "rw").getChannel(); wb=new XSSFWorkbook(fileInput); sheet=wb.getSheet("message"); // fileLock=fileChannel.lock(); }else{//文件不存在 // 新建 isFile=false; wb=new XSSFWorkbook(); sheet=wb.createSheet("message"); } this.filePath=filePath; this.headnum=headnum; addHeader(title); } catch (Exception e) { e.printStackTrace(); } } /** * 获取最后一个数据行号 * @return */ public int getLastDataRowNum(){ return this.sheet.getLastRowNum()+headnum; } public void setData(Row row,T data){ int colunm = 0; Object val = null; for (Object[] os : annotationList){ if(os[1] instanceof Field){ val = Reflections.invokeGetter(data, ((Field)os[1]).getName()); }else if (os[1] instanceof Method){ val = Reflections.invokeMethod(data, ((Method)os[1]).getName(), new Class[] {}, new Object[] {}); } this.addCell(row, colunm++, val, 2, Class.class); } } public void setListData(int rownum,List<T> data){ for(T m:data){ Row row= sheet.createRow(rownum++); setData(row, m); } } public abstract void appenList(List<T> listdata); /** * 添加一个单元格 * @param row 添加的行 * @param column 添加列号 * @param val 添加值 * @param align 对齐方式（1：靠左；2：居中；3：靠右） * @return 单元格对象 */ private Cell addCell(Row row, int column, Object val, int align, Class<?> fieldType){ Cell cell = row.createCell(column); String cellFormatString = "@"; try { if(val == null){ cell.setCellValue(""); }else if(fieldType != Class.class){ cell.setCellValue((String)fieldType.getMethod("setValue", Object.class).invoke(null, val)); }else{ if(val instanceof String) { cell.setCellValue((String) val); }else if(val instanceof Integer) { cell.setCellValue((Integer) val); cellFormatString = "0"; }else if(val instanceof Long) { cell.setCellValue((Long) val); cellFormatString = "0"; }else if(val instanceof Double) { cell.setCellValue((Double) val); cellFormatString = "0.00"; }else if(val instanceof Float) { cell.setCellValue((Float) val); cellFormatString = "0.00"; }else if(val instanceof Date) { cell.setCellValue((Date) val); cellFormatString = "yyyy-MM-dd HH:mm"; }else { cell.setCellValue((String)Class.forName(this.getClass().getName().replaceAll(this.getClass().getSimpleName(), "fieldtype."+val.getClass().getSimpleName()+"Type")).getMethod("setValue", Object.class).invoke(null, val)); } } if (val != null){ CellStyle style = styles.get("data_column_"+column); if (style == null){ style = wb.createCellStyle(); style.cloneStyleFrom(styles.get("data"+(align>=1&&align<=3?align:""))); style.setDataFormat(wb.createDataFormat().getFormat(cellFormatString)); styles.put("data_column_" + column, style); } cell.setCellStyle(style); } } catch (Exception ex) { cell.setCellValue(val.toString()); } return cell; } private void addHeader(String title){ List<Field> listField= Arrays.asList(clazz.getDeclaredFields()); for(Field field:listField){ ChatField fieldClass=field.getAnnotation(ChatField.class); if(fieldClass!=null){ annotationList.add(new Object[]{fieldClass,field}); //