用prepareStatement、resultSet写的excel实例分析

/** Map<String, Object> map=writeToExl( sql,path, filename, originalPath);

file=(File) map.get("file");

* 生成EXCLE 文件

*

* @param sql

* 数据查询sql

* @param path

* 文件生成路径

* @param filename

* 文件名

* @param originalPath

* 原始excle模版路径

* @return

*/

@SuppressWarnings("deprecation")

public Map<String, Object> writeToExl( String sql,

String path, String filename, String originalPath) {

if (StringUtils.isBlank(path)) {

path = SettingService.tempFilePath();//SettingService类的tempFilePath()方法主要是用来获取生成excel存档的文件夹

File f = new File(path);

//如果没有该文件夹，则重新生成

if (!f.exists()) {

f.mkdirs();

}

}

//excel文件名如果没有指定的，则随机生成一个为文件名

if (StringUtils.isBlank(filename)) {

filename = UUID.randomUUID().toString();

}

PreparedStatement st = null;//PreparedStatement 可以达到预处理

ResultSet rs = null;/*结果集(ResultSet)是数据中查询结果返回的一种对象，可以说结果集是一个存储查询结果的对象，但是结果集并不仅仅具有存储的功能，他同时还具有操纵数据的功能，可能完成对数据的更新等.*/

File file = null;

Map<String, Object> returnMap = new HashMap<String, Object>();

try {

// 总记录数

Long count = null;

String countSql = "SELECT COUNT(*) FROM ("

+ sql+")";

if (!StringUtils.isBlank(countSql)) {

count = Utils.converToLong(getSession()

.createSQLQuery(countSql).uniqueResult());//求数据数目

} else {

count = 1000L;

}

// returnMap.put("count", count);

// 执行 PrepareStatement

st = ((SessionImpl) getSession()).getBatcher()

.prepareStatement(sql);

rs = st.executeQuery();

// 头行汉字

ResultSetMetaData metadata = rs.getMetaData();

int columnCount = metadata.getColumnCount();

List<Integer> columns = new ArrayList<Integer>(columnCount);

List<String> columnNames = new ArrayList<String>(columnCount);

int col = 0;

//数据列

for (int i = 0; i < columnCount; i++) {

// nextLine[i] = metadata.getColumnName(i + 1);

String n = metadata.getColumnName(i + 1);

String cn = n;

if (!StringUtils.isBlank(cn)) {

columns.add(i);

columnNames.add(cn);

// nmap.put(cn, i);

}

}

HSSFWorkbook wb=null;

FileOutputStream fileOut=null;

String tmpFileDir = null;

boolean merge = false;

// 计算是否需要拆分成几个文件

if (count >= Report.MAX_SHEET_NUMBER) {

merge = true;

tmpFileDir = FilenameUtils.normalize(path + "/"

+ UUID.randomUUID().toString());

new File(tmpFileDir).mkdirs();

file = new File(FilenameUtils.normalize(path + "/"

+ StringUtils.substringBefore(filename, ".") + ".zip"));

returnMap.put("suffix", "zip");

} else {

file = new File(FilenameUtils.normalize(path + "/"

+ StringUtils.substringBefore(filename, ".") + ".xls"));

returnMap.put("suffix", "xls");

}

returnMap.put("file", file);

int pageIndex = 1;

int rowIndex = 2;

HSSFSheet sheet=null;

HSSFRow row =null;

POIFSFileSystem fs=null;

boolean isBlank = true;

boolean writeFlag = false;

wb = new HSSFWorkbook();

FileUtils.copyFile(

new File(FilenameUtils.normalize(SimpleFileUtils

.getRootPath()+ originalPath)),file, true);

fs = new POIFSFileSystem(new FileInputStream(file.getPath()));

wb = new HSSFWorkbook(fs);

while (rs.next()) {

if (rowIndex == 2) {

File _file = file;

// fileWriter = new OutputStreamWriter(new FileOutputStream(

// _file), "GBK");

if (merge) {

isBlank = false;

_file = new File(tmpFileDir + "/" + pageIndex + ".xls");

}

FileUtils.copyFile(

new File(FilenameUtils.normalize(SimpleFileUtils

.getRootPath()+ originalPath)),_file, true);//复制模版到目标excel

fs = new POIFSFileSystem(new FileInputStream(_file.getPath()));

wb = new HSSFWorkbook(fs);

while (wb.getSheetAt(0).getRow(1).getCell(col) != null) {

columns.add(col);

col++;

}

}

row = wb.getSheetAt(0).createRow(rowIndex);

// String[] nextLine = new String[columns.size()];

int j = 0;

for (int i = 0; i < columnCount; i++) {

if (columns.contains(i)) {

HSSFCell cell = row.createCell(j++);

String value = HibernateHelper.getColumnStrValue(rs,

metadata.getColumnType(i + 1), i + 1);

cell.setCellValue(value);

}

}

rowIndex = rowIndex + 1;

if (rowIndex >= Report.MAX_SHEET_NUMBER) {

fileOut = new FileOutputStream(tmpFileDir + "/" + pageIndex + ".xls");

wb.write(fileOut);

fileOut.close();

rowIndex = 2;

pageIndex = pageIndex + 1;

writeFlag = true;

}

}

if(writeFlag) {

fileOut = new FileOutputStream(tmpFileDir + "/" + pageIndex + ".xls");

wb.write(fileOut);

fileOut.close();

}

if (isBlank) {

fileOut = new FileOutputStream(file.getPath());

wb.write(fileOut);

fileOut.close();

}

// 合并文件

if (merge) {

Attachment.compressed(tmpFileDir, file);

// 删除临时目录

FileUtils.deleteDirectory(new File(tmpFileDir));

}

} catch (IOException e) {

e.printStackTrace();

throw new BusinessException(e.toString());

} catch (HibernateException e) {

e.printStackTrace();

throw new BusinessException(e.toString());

} catch (SQLException e) {

e.printStackTrace();

throw new BusinessException(e.toString());

} finally {

if (rs != null) {

try {

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if (st != null) {

try {

st.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

return returnMap;

}