扩展Struts2,傻瓜化将数据导出为excel
以前做开发，在有数据导出为excel的时候，不加思索就一个cell一个cell地拼凑完成一个excel内存流，输入出到客户端了事，有天想这些代码80%都是重复的，能不能不那么麻烦地ctrl c、ctrl v来做这件事。尝试了下，还可以。（代码部份中是演示）首先定义一个Annotation
@Retention(RetentionPolicy.RUNTIME)public @interface Excel {String title() default "";}
在需要导出为excel的类上加上此Excel注解，如：
class User {public User(String name, Integer age) {this.name = name;this.age = age;}private String name;private Integer age;@Excel(title = "姓名")public String getName() {return name;}public void setName(String name) {this.name = name;}@Excel(title = "年龄")public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}}
现在相当于配置内容有了，只需写一个工具类，完成向excel数据格式的转换。
这有个简单实现：
public static void export(List list, OutputStream os) {List<String> titles = new ArrayList<String>();Hashtable<String, List> data = parseData(list, titles);try { builderExcel(data, titles, list.size(), os);} catch (Exception e) { e.printStackTrace();}}private static void builderExcel(Hashtable<String, List> data, List<String> titles, int len, OutputStream os) throws Exception {WritableWorkbook workbook = Workbook.createWorkbook(os);WritableSheet ws = workbook.createSheet("sheet1", 0);//for (int i = 0; i < titles.size(); i++) { Label labelC = new Label(i, 0, titles.get(i)); ws.setColumnView(i, 20); ws.addCell(labelC); }for (int i = 0; i < len; i++) { for (int j = 0; j < titles.size(); j++) { List<Object> context = data.get(titles.get(j)); Object o = context.get(i); WritableCell labelC = null; if (o instanceof String) { labelC = new Label(j, i + 1, o.toString()); } else if(o instanceof Double) { labelC = new Number(j, i + 1, (Double)o); } else if(o instanceof Date) { labelC = new DateTime(j, i + 1, (Date)o); } ws.addCell(labelC); }}workbook.write();workbook.close();}private static Hashtable parseData(List list, List titles) {Hashtable<String, List> data = new Hashtable<String, List>();for (Object obj : list) { Method[] methods = obj.getClass().getMethods(); for (Method m : methods) { if (m.isAnnotationPresent(Excel.class)) { Excel excel = m.getAnnotation(Excel.class); String title = excel.title(); List<Object> cols = data.get(title); if (cols == null) { titles.add(title); cols = new ArrayList<Object>(); } try { cols.add(m.invoke(obj)); } catch (IllegalArgumentException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvocationTargetException e) { // TODO Auto-generated catch block e.printStackTrace(); } data.put(title, cols); } }}return data;}}
最后一步，扩展struts2的resulttype.public class ExcelResult extends StrutsResultSupport { private String dataList = "dataList"; private String fileName = "fileName"; protected void doExecute(String arg0, ActionInvocation actionInvocation) throws Exception { ActionContext ctx = actionInvocation.getInvocationContext(); HttpServletRequest request = (HttpServletRequest) ctx .get(org.apache.struts2.StrutsStatics.HTTP_REQUEST); HttpServletResponse response = (HttpServletResponse) ctx .get(org.apache.struts2.StrutsStatics.HTTP_RESPONSE); String excelfile = (String) request.getAttribute(fileName); setXlsHeader(response, excelfile); OutputStream os = response.getOutputStream(); List list = (List) request.getAttribute(dataList); ExcelExporter.export(list, os); os.close(); } public void setDataList(String dataList) { this.dataList = dataList; } public void setFileName(String fileName) { this.fileName = fileName; } private void setXlsHeader(HttpServletResponse rs, String fn) throws UnsupportedEncodingException { rs.setContentType("application/vnd.ms-excel"); String fileName = new String(fn.getBytes("GBK"), "ISO-8859-1"); rs.setHeader("Content-disposition", "attachment; filename=" + fileName); } }
现在看看程序员需要做的事：
List<User> userList = userService.findAll();request.setAttribute("dataList",userList);
在struts2的配置文件中加入
<result name="success" type="excel">
</result>
当然你得在需要导出的类中加入Excel的注解和定义一下excel的resulttype.
页:
[1]