导出Excel工具类

public class ExcelUtil
{
public static <T> void listToExcel(List<T> list, LinkedHashMap<String, String> fieldMap, String sheetName, OutputStream out)
throws Exception
{
if ((list.size() == 0) || (list == null)) {
throw new Exception("数据源中没有任何数据");
}
int sheetSize = list.size();
if ((sheetSize > 65535) || (sheetSize < 1)) {
sheetSize = 65535;
}

try
{
WritableWorkbook wwb = Workbook.createWorkbook(out);

int sheetNum = list.size() % sheetSize == 0 ? list.size() /
sheetSize : list.size() / sheetSize + 1;

for (int i = 0; i < sheetNum; i++)
{
if (1 == sheetNum) {
WritableSheet sheet = wwb.createSheet(sheetName, i);
fillSheet(sheet, list, fieldMap, 0, list.size() - 1);
}
else {
WritableSheet sheet = wwb.createSheet(sheetName + (i + 1), i);

int firstIndex = i * sheetSize;
int lastIndex = (i + 1) * sheetSize - 1 > list.size() - 1 ? list
.size() - 1 : (i + 1) * sheetSize - 1;

fillSheet(sheet, list, fieldMap, firstIndex, lastIndex);
}
}
wwb.write();
wwb.close();
} catch (Exception e) {
e.printStackTrace();
}
}

public static <T> void listToExcel(List<T> list, LinkedHashMap<String, String> fieldMap, String sheetName, HttpServletResponse response)
{
String fileName = new SimpleDateFormat("yyyy-MM-dd").format(
new Date()).toString();

response.reset();
response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-disposition", "attachment; filename=schedule_" +
fileName + ".xls");
try
{
OutputStream out = response.getOutputStream();
listToExcel(list, fieldMap, sheetName, out);
} catch (Exception e) {
e.printStackTrace();
}
}

private static void setColumnAutoSize(WritableSheet ws, int extraWith)
{
for (int i = 0; i < ws.getColumns(); i++) {
int colWith = 0;
for (int j = 0; j < ws.getRows(); j++) {
String content = ws.getCell(i, j).getContents().toString();
int cellWith = content.length();
if (colWith < cellWith) {
colWith = cellWith;
}
}

ws.setColumnView(i, colWith + extraWith);
}
}

public static <T> List<T> excelToList(InputStream in, String sheetName, Class<T> entityClass, LinkedHashMap<String, String> fieldMap)
{
List resultList = new ArrayList();
try
{
Workbook wb = Workbook.getWorkbook(in);

Sheet sheet = wb.getSheet(sheetName);

int realRows = 0;
for (int i = 0; i < sheet.getRows(); i++)
{
int nullCols = 0;
for (int j = 0; j < sheet.getColumns(); j++) {
Cell currentCell = sheet.getCell(j, i);
if ((currentCell == null) ||
("".equals(currentCell.getContents().toString()))) {
nullCols++;
}
}
if (nullCols == sheet.getColumns()) {
break;
}
realRows++;
}

if (realRows <= 1) {
throw new Exception("Excel文件中没有任何数据");
}
Cell[] firstRow = sheet.getRow(0);
String[] excelFieldNames = new String[firstRow.length];

for (int i = 0; i < firstRow.length; i++) {
excelFieldNames[i] = firstRow[i].getContents().toString()
.trim();
}

boolean isExist = true;
List excelFieldList = Arrays.asList(excelFieldNames);
for (String cnName : fieldMap.keySet()) {
if (!excelFieldList.contains(cnName)) {
isExist = false;
break;
}
}

if (!isExist) {
throw new Exception("Excel中缺少必要的字段，或字段名称有误");
}

LinkedHashMap colMap = new LinkedHashMap();
for (int i = 0; i < excelFieldNames.length; i++) {
colMap.put(excelFieldNames[i], Integer.valueOf(firstRow[i].getColumn()));
}

for (int i = 1; i < realRows; i++)
{
Object entity = entityClass.newInstance();

for (Map.Entry entry : fieldMap.entrySet())
{
String cnNormalName = (String)entry.getKey();

String enNormalName = (String)entry.getValue();

int col = ((Integer)colMap.get(cnNormalName)).intValue();

String content = sheet.getCell(col, i).getContents()
.toString().trim();
ReflectUtil.setProperty(entity, enNormalName, content);
}
resultList.add(entity);
}
} catch (Exception e) {
e.printStackTrace();
}
return resultList;
}

private static <T> void fillSheet(WritableSheet sheet, List<T> list, LinkedHashMap<String, String> fieldMap, int firstIndex, int lastIndex)
throws Exception
{
String[] enFields = new String[fieldMap.size()];
String[] cnFields = new String[fieldMap.size()];

int count = 0;
for (Map.Entry entry : fieldMap.entrySet()) {
enFields[count] = ((String)entry.getKey());
cnFields[count] = ((String)entry.getValue());
count++;
}

for (int i = 0; i < cnFields.length; i++)
{
WritableFont font1 = new WritableFont(WritableFont.TIMES,
12, WritableFont.BOLD);
WritableCellFormat format1 = new WritableCellFormat(font1);
format1.setAlignment(Alignment.CENTRE);
Label label = new Label(i, 0, cnFields[i]);
label.setCellFormat(format1);
sheet.addCell(label);
}

int rowNo = 1;
for (int index = firstIndex; index <= lastIndex; index++)
{
Object item = list.get(index);
for (int i = 0; i < enFields.length; i++) {
Object objValue = null;
objValue = ReflectUtil.getNestedProperty(item, enFields[i]);
String fieldValue = objValue == null ? "" : objValue.toString();
Label label = new Label(i, rowNo, fieldValue);
sheet.addCell(label);
}
rowNo++;
}

setColumnAutoSize(sheet, 5);
}
}