Java 创建Excel并逐行写入数据

package com.xxx.common.excel;import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.Map;import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;public class ExcelWrite {
private static HSSFWorkbook workbook = null; /**
* 判断文件是否存在.
* @param fileDir 文件路径
* @return
*/
public static boolean fileExist(String fileDir){
boolean flag = false;
File file = new File(fileDir);
flag = file.exists();
return flag;
}
/**
* 判断文件的sheet是否存在.
* @param fileDir 文件路径
* @param sheetName 表格索引名
* @return
*/
public static boolean sheetExist(String fileDir,String sheetName) throws Exception{
boolean flag = false;
File file = new File(fileDir);
if(file.exists()){ //文件存在
//创建workbook
try {
workbook = new HSSFWorkbook(new FileInputStream(file));
//添加Worksheet（不添加sheet时生成的xls文件打开时会报错)
HSSFSheet sheet = workbook.getSheet(sheetName);
if(sheet!=null)
flag = true;
} catch (Exception e) {
throw e;
} }else{ //文件不存在
flag = false;
}
return flag;
}
/**
* 创建新excel.
* @param fileDir excel的路径
* @param sheetName 要创建的表格索引
* @param titleRow excel的第一行即表格头
*/
public static void createExcel(String fileDir,String sheetName,String titleRow[]) throws Exception{
//创建workbook
workbook = new HSSFWorkbook();
//添加Worksheet（不添加sheet时生成的xls文件打开时会报错)
HSSFSheet sheet1 = workbook.createSheet(sheetName);
//新建文件
FileOutputStream out = null;
try {
//添加表头
HSSFRow row = workbook.getSheet(sheetName).createRow(0); //创建第一行
for(short i = 0;i < titleRow.length;i++){
HSSFCell cell = row.createCell(i);
cell.setCellValue(titleRow[i]);
}
out = new FileOutputStream(fileDir);
workbook.write(out);
} catch (Exception e) {
throw e;
} finally {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 删除文件.
* @param fileDir 文件路径
*/
public static boolean deleteExcel(String fileDir) {
boolean flag = false;
File file = new File(fileDir);
// 判断目录或文件是否存在
if (!file.exists()) { // 不存在返回 false
return flag;
} else {
// 判断是否为文件
if (file.isFile()) { // 为文件时调用删除文件方法
file.delete();
flag = true;
}
}
return flag;
}
/**
* 往excel中写入(已存在的数据无法写入).
* @param fileDir 文件路径
* @param sheetName 表格索引
* @param object
* @throws Exception
*/
public static void writeToExcel(String fileDir,String sheetName,List<Map> mapList) throws Exception{
//创建workbook
File file = new File(fileDir);
try {
workbook = new HSSFWorkbook(new FileInputStream(file));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//流
FileOutputStream out = null;
HSSFSheet sheet = workbook.getSheet(sheetName);
// 获取表格的总行数
// int rowCount = sheet.getLastRowNum() + 1; // 需要加一
// 获取表头的列数
int columnCount = sheet.getRow(0).getLastCellNum()+1;
try {
// 获得表头行对象
HSSFRow titleRow = sheet.getRow(0);
if(titleRow!=null){
for(int rowId=0;rowId<mapList.size();rowId++){
Map map = mapList.get(rowId);
HSSFRow newRow=sheet.createRow(rowId+1);
for (short columnIndex = 0; columnIndex < columnCount; columnIndex++) { //遍历表头
String mapKey = titleRow.getCell(columnIndex).toString().trim().toString().trim();
HSSFCell cell = newRow.createCell(columnIndex);
cell.setCellValue(map.get(mapKey)==null ? null : map.get(mapKey).toString());
}
}
} out = new FileOutputStream(fileDir);
workbook.write(out);
} catch (Exception e) {
throw e;
} finally {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} public static void main(String[] args) {
/*判断文件是否存在
System.out.println(ExcelWrite.fileExist("E:/test2.xls"));
//创建文件
String title[] = {"id","name","password"};
ExcelWrite.createExcel("E:/test2.xls","sheet1",title);
List<Map> list=new ArrayList<Map>();
Map<String,String> map=new HashMap<String,String>();
map.put("id", "111");
map.put("name", "张三");
map.put("password", "111！@#"); Map<String,String> map2=new HashMap<String,String>();
map2.put("id", "222");
map2.put("name", "李四");
map2.put("password", "222！@#");
list.add(map);
list.add(map2);
ExcelWrite.writeToExcel("E:/test2.xls","sheet1",list); String sql="select aaa,bbb,ccc from dddd";
String sqlForSplit = sql.substring(sql.toLowerCase().indexOf("select")+6,sql.toLowerCase().indexOf("from")).trim();
String sqlRemoveFrom=sql.substring(sql.toLowerCase().indexOf("from")+5).trim();
System.out.println(sqlRemoveFrom);
String tableName=sqlRemoveFrom.indexOf(" ")==-1 ? sqlRemoveFrom : sqlRemoveFrom.substring(0,sqlRemoveFrom.indexOf(" "));
System.out.println(tableName);
*/ }
}