自己封装的POI + Struts2 实现Excel导出工具包
1、注解

package lml.excel.annotation;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;/** * @author MerryGrass * 自定义注解 */@Retention(RetentionPolicy.RUNTIME)public @interface PropertyAnnotation{/** * 属性名称描述 （默认值为 "Unknown"） * @return String */String PropertyName() default "Unknown";/** * 属性索引键 （默认值为 "-1"） * @return int */int PropertySortKey() default -1;}

2、接口

/** *  */package lml.excel.service;import java.util.List;public interface CreateExcel {/** * 创建一个sheet * @param sheetName * sheet名字 */public void createSheet(String sheetName);/** * 创建一行 */public void createRow();/** * 创建一个单元格 * @param cellNum * 单元格所属位置 */public void createCell(int cellNum);/** * 设置一个单元格内容 * @param data * 单元格内容 * @param cellNum * 单元格所属位置 */public void setCell(String data, int cellNum);/**  * 设置标题内容  * @param title  * 标题  * @return CreateExcel  */public CreateExcel setTitle(String title);/** * 设置表头内容 * @return CreateExcel */public CreateExcel setHead();/** * 设置单元格内容 * @param datas * 单元格数据 * @return CreateExcel */public CreateExcel setCellData(List<?> datas) throws Exception;}

/** *  */package lml.excel.service;import java.util.List;public interface ExcelInfo { /**  * 获取表头数据  * @return String[] 表头数据所组成的数组  */public List<String> getHeaders();/** * 获取有效属性所对应的值 * @param obj * 对象 * @param methodName * 方法名 * @return String */public String getContent(Object obj, String methodName) throws Exception;}

package lml.excel.service;import java.io.InputStream;import java.util.List;import org.apache.poi.hssf.usermodel.HSSFWorkbook;public interface ExcelService {/** * 获取Excel * @param clazz * 类名 * @param datas * 数据 * @param title * 标题 * @return */public InputStream getExcelInputStream(String clazz, List<?> datas, String title,List<String> fieldsName) throws Exception;/** * 创建Excel * @param clazz * 类名 * @param datas * 数据 * @param title * 标题 * @return */public HSSFWorkbook createExcel(String clazz, List<?> datas, String title,List<String> fieldsName) throws Exception;}

3、实现类

package lml.excel.service.impl;import java.util.List;import lml.excel.service.CreateExcel;import org.apache.poi.hssf.usermodel.HSSFCell;import org.apache.poi.hssf.usermodel.HSSFCellStyle;import org.apache.poi.hssf.usermodel.HSSFFont;import org.apache.poi.hssf.usermodel.HSSFRow;import org.apache.poi.hssf.usermodel.HSSFSheet;import org.apache.poi.hssf.usermodel.HSSFWorkbook;import org.apache.poi.hssf.util.Region;public class CreateExcelImpl implements CreateExcel {private HSSFWorkbook wb = null;private HSSFSheet sheet = null;private HSSFRow row = null;private HSSFCell cell = null;private ExcelInfoImpl excelInfo = null;private int rowNum = 0; //当前需要创建的行数，初始化为0/** * 初始化HSSFWorkbook，并默认创建一个sheet * @param className * 类的全路径 */public CreateExcelImpl(String className,List<String> fieldsName){wb = new HSSFWorkbook();createSheet("sheet1");excelInfo = new ExcelInfoImpl(className,fieldsName);}/** * 创建一个单元格 * @param cellNum * 单元格所属位置 */public void createCell(int cellNum) {cell = row.createCell((short)cellNum);}/** * 创建一行，并把当前行加1 */public void createRow() {row = sheet.createRow(rowNum);rowNum++;}/** * 创建一个sheet * @param sheetName * sheet名字 */public void createSheet(String sheetName) {sheet = wb.createSheet(sheetName);}/** * 设置一个单元格内容 * @param data * 单元格内容 * @param cellNum * 单元格所属位置 */public void setCell(String data, int cellNum) {createCell(cellNum);cell.setEncoding(HSSFCell.ENCODING_UTF_16);cell.setCellValue(data);}/** * 设置单元格内容 * @param datas * 单元格数据 * @return 当前对象 */public CreateExcelImpl setCellData(List<?> datas) throws Exception{List<String> list = excelInfo.getPropertys();for(int j = 0; j < datas.size(); j++){Object obj = datas.get(j);createRow();for(int i = 0; i < list.size(); i++){setCell(excelInfo.getContent(obj, list.get(i)),i);}}return this;}/** * 设置表头内容 * @return 当前对象 */public CreateExcelImpl setHead() {List<String> datas = excelInfo.getPropertyNames();if(datas.size() == 0){datas = excelInfo.getHeaders();}createRow();for(int i = 0; i < datas.size(); i++){setCell((String)datas.get(i), i);}return this;}/**  * 设置标题内容  * @param title  * 标题  * @return 当前对象  */public CreateExcelImpl setTitle(String title) {this.createRow();this.createCell(0);HSSFFont titlefont = wb.createFont();titlefont.setFontName("Arial");titlefont.setBoldweight(titlefont.BOLDWEIGHT_BOLD);titlefont.setFontHeight((short)400);HSSFCellStyle titleStyle = wb.createCellStyle();titleStyle.setFont(titlefont);titleStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);cell.setCellStyle(titleStyle);cell.setEncoding(HSSFCell.ENCODING_UTF_16);cell.setCellValue(title);sheet.addMergedRegion(new Region(0, (short)0, 1, (short)(excelInfo.getNum()-1)));rowNum++;return this;}/** * 获取HSSFWorkbook * @return HSSFWorkbook */public HSSFWorkbook getWb() {return wb;}}

package lml.excel.service.impl;import java.lang.reflect.Field;import java.lang.reflect.Method;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import lml.excel.annotation.PropertyAnnotation;import lml.excel.service.ExcelInfo;/** * 获取相应类实例的有效信息 * */@SuppressWarnings("unchecked")public class ExcelInfoImpl implements ExcelInfo {private Class clazz = null;//有效属性个数private int num = 0;//有效属性数组private List<String> propertys = new ArrayList<String>();//有效属性信息数组List<String> propertyNames = new ArrayList<String>();//需导出字段List<String> fieldsName = new ArrayList<String>();//有效属性排序键//List<Integer> sortKey = new ArrayList<Integer>();/** * 得到类实例 * @param className * 类的全路径 */public ExcelInfoImpl(String className,List<String> fieldsName){this.fieldsName = fieldsName;try{clazz = Class.forName(className);}catch(Exception e){e.printStackTrace();}}/** * 获取有效属性所对应的值 * @param methodName * 有效属性 * @return String  */@SuppressWarnings("unchecked")public String getContent(Object obj, String methodName) throws Exception {String realMethodName = "get" + methodName.substring(0,1).toUpperCase() + methodName.substring(1);Method method = clazz.getMethod(realMethodName, new Class[]{});if(null == method.invoke(obj, new Object[]{}) || "".equals(method.invoke(obj, new Object[]{}))){return "";}else{return method.invoke(obj, new Object[]{}).toString();}}/**  * 获取表头数据  * @return String[] 表头数据所组成的数组  */@SuppressWarnings("unchecked")public List<String> getHeaders() {//得到类实例的所有属性Field[] fields = clazz.getDeclaredFields();//属性信息String propertyName = "";int PropertySortKey = 0;Map mapPropertys = new HashMap();Map mapPropertyNames = new HashMap();boolean flag = false;//通过循环比较得到有效属性if(0 != this.fieldsName.size()){for(int i = 0;i < fields.length;i++){if(null == fields[i].getAnnotation(PropertyAnnotation.class)){continue;}propertyName = fields[i].getAnnotation(PropertyAnnotation.class).PropertyName();for(String str : fieldsName){if(str.equals(propertyName)){propertys.add(fields[i].getName());propertyNames.add(propertyName);}}}}else{//通过循环比较得到有效属性for(int i = 0; i < fields.length; i++){//得到相应属性的信息if(null == fields[i].getAnnotation(PropertyAnnotation.class)){continue;}propertyName = fields[i].getAnnotation(PropertyAnnotation.class).PropertyName();PropertySortKey = fields[i].getAnnotation(PropertyAnnotation.class).PropertySortKey();//判断是否为有效属性if(null != propertyName){if(!flag){if(PropertySortKey == -1){if("Unknown".equals(propertyName)){propertys.add(fields[i].getName());propertyNames.add(fields[i].getName());}else{propertys.add(fields[i].getName());propertyNames.add(propertyName);}}else{flag = true;}}if(flag){if("Unknown".equals(propertyName)){mapPropertys.put(PropertySortKey, fields[i].getName());mapPropertyNames.put(PropertySortKey, fields[i].getName());}else{mapPropertys.put(PropertySortKey, fields[i].getName());mapPropertyNames.put(PropertySortKey, propertyName);}}}}if(flag){sortPropertys(mapPropertys,mapPropertyNames);}}return propertyNames;}//有效属性排序  public void sortPropertys(Map mapPropertys, Map mapPropertyNames){for(int i = 1; i <= mapPropertys.size(); i++){propertys.add((String)mapPropertys.get(i));propertyNames.add((String)mapPropertyNames.get(i));}}/** * 获取有效属性数组 * @return */public List<String> getPropertys() {return propertys;}/** * 获取有效属性信息 * @return */public List<String> getPropertyNames() {return propertyNames;}/** * 获取有效属性个数 * @return */public int getNum() {num = getPropertys().size();if(num == 0){getHeaders();num = getPropertys().size();}return num;}}

package lml.excel.service.impl;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import java.util.List;import org.apache.poi.hssf.usermodel.HSSFWorkbook;import lml.excel.service.ExcelService;/** * 创建并获取Excel的服务类 * */public class ExcelServiceImpl implements ExcelService {/** * 创建Excel * @param clazz * 类名 * @param datas * 数据 * @param title * 标题 * @return */public HSSFWorkbook createExcel(String clazz, List<?> datas, String title,List<String> fieldsName) throws Exception{CreateExcelImpl createExcel = new CreateExcelImpl(clazz,fieldsName); //创建标题、表头、以及单元格数据createExcel.setTitle(title).setHead().setCellData(datas);return createExcel.getWb();}/** * 获取Excel * @param clazz * 类名 * @param datas * 数据 * @param title * 标题 * @return */public InputStream getExcelInputStream(String clazz, List<?> datas,String title,List<String> fieldsName) throws Exception {ByteArrayOutputStream os = new ByteArrayOutputStream();try{createExcel(clazz, datas, title,fieldsName).write(os);}catch (IOException e){e.printStackTrace();}byte[] content = os.toByteArray();InputStream is = new ByteArrayInputStream(content);return is;}}

4、Demo Action

package lml.sf.pojo.action;import java.io.InputStream;import java.io.UnsupportedEncodingException;import java.util.ArrayList;import java.util.List;import lml.base.BaseDAO;import lml.excel.service.impl.ExcelServiceImpl;import lml.sf.pojo.V_SF_STUINFO;import com.opensymphony.xwork2.ActionSupport;public class STUINFOAction extends ActionSupport {private String filename;private String Tempstr;private List<String> fieldsName = new ArrayList<String>();private InputStream downStream;public String getFilename() {try {filename = new String(filename.getBytes(),"ISO8859-1");} catch (UnsupportedEncodingException e) {e.printStackTrace();}return filename + ".xls";}public void setFilename(String filename) {this.filename = filename;}public List<String> getFieldsName() {return fieldsName;}public void setFieldsName(List<String> fieldsName) {this.fieldsName = fieldsName;}public InputStream getDownStream() throws Exception{return downStream;}public void setDownStream(InputStream downStream) {this.downStream = downStream;}public String getTempstr() {return Tempstr;}public void setTempstr(String tempstr) {Tempstr = tempstr;}public String initExcel(){return SUCCESS;}@Overridepublic String execute() throws Exception {return "excelinit";}public String doexport() throws Exception{if(null != Tempstr && !"".equals(Tempstr)){String[] strArray = Tempstr.split(",");for(int i=0;i<strArray.length;i++){if(null != strArray[i] && !"".equals(strArray[i])){this.fieldsName.add(strArray[i]);}}this.filename = "收费学生信息";BaseDAO DAO = new BaseDAO();List<V_SF_STUINFO> datas = new ArrayList<V_SF_STUINFO>();datas = DAO.getAll(V_SF_STUINFO.class);ExcelServiceImpl excel = new ExcelServiceImpl();this.downStream = excel.getExcelInputStream("lml.sf.pojo.V_SF_STUINFO", datas, "收费学生信息导出Excel_Demo",fieldsName);return SUCCESS;}return ERROR;}public String ioexport() throws Exception{this.filename = "收费学生信息";BaseDAO DAO = new BaseDAO();List<V_SF_STUINFO> datas = new ArrayList<V_SF_STUINFO>();datas = DAO.getAll(V_SF_STUINFO.class);ExcelServiceImpl excel = new ExcelServiceImpl();this.downStream = excel.getExcelInputStream("lml.sf.pojo.V_SF_STUINFO", datas, "收费学生信息导出Excel_Demo",new ArrayList<String>());return SUCCESS;}}

5、struts.xml 配置

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"    "http://struts.apache.org/dtds/struts-2.0.dtd"><struts><constant name="struts.custom.il8n.resources" value="message"></constant><constant name="struts.i18n.encoding" value="UTF-8"></constant><package name="excel" extends="struts-default"><action name="Export" method="doexport"><result name="success" type="stream"><param name="contentType">application/vnd.ms-excel</param><param name="contentDisposition">attachment;filename=${filename}</param><param name="inputName">downStream</param></result><result name="error">/STUINFO.jsp</result></action></package></struts>

package lml.sf.pojo;import lml.excel.annotation.PropertyAnnotation;/** * @author 报到收费学生信息视图 * @hibernate.class table="V_SF_STUINFO" */public class V_SF_STUINFO {/** * 学生ID *  * @hibernate.id generator-/>  楼主的源码我已经用上了，很好用，不过如果生成的EXCEL如果需要在标题下面再输出一些制表单位信息，表最下面输出时间信息，用现有的类可以实现吗？还有，楼主说的改进主要改动的是哪些方面？  楼主的源码我已经用上了，很好用，不过如果生成的EXCEL如果需要在标题下面再输出一些制表单位信息，表最下面输出时间信息，用现有的类可以实现吗？还有，楼主说的改进主要改动的是哪些方面？
这个问题是很好解决的，后面的修正功能上也没太大的变化只是在版本的升级和代码的优化！    5 楼    lemon0    2011-09-02              非常不错。 刚好用到，先试试，有问题再来讨论