POI realization of import and export excel

One. Imported into excel

NOTE: POI herein is ssm frame base prior to the introduction of the

1. dependence introduction

<dependency>
      <groupId>org.apache.poi</groupId>
      <artifactId>poi</artifactId>
      <version>3.9</version>
    </dependency>
    <dependency>
      <groupId>org.apache.poi</groupId>
      <artifactId>poi-ooxml</artifactId>
      <version>3.9</version>
    </dependency>

2. Write POIUtil class

com.exp.utils Package; 

Import com.exp.model.User; 
Import the org.apache.poi.hssf.usermodel *;. 
Import org.apache.poi.ss.util.CellRangeAddress; 

Import java.io.FileOutputStream; 
Import a java.io.OutputStream; 
Import java.util.List; 


public class POIUtil { 

    public static void Export (List <the User> userList) throws Exception { 
        position designating data storage // 
        the OutputStream the outputStream a FileOutputStream new new = ( "D: \\ Test .xls "); 
        // create a workbook 1. 
        HSSFWorkbook workbook = new new HSSFWorkbook (); 
        . 2 // create a worksheet sheet 
        HSSFSheet sheet = workbook.createSheet (" the Test "); 
        // List <the User> = userList userService.selectAll ();
        // constructor parameter in turn represents the starting line up to the line, start column, as of column
        Region = new new CellRangeAddress CellRangeAddress (0, 0, 0,. 3); 
        sheet.addMergedRegion (Region); 

        HSSFCellStyle style = workbook.createCellStyle (); 
        // horizontally centered 
        style.setAlignment (HSSFCellStyle.ALIGN_CENTER); 
        // vertically centered 
        style. setVerticalAlignment (HSSFCellStyle.VERTICAL_CENTER); 

        HSSFRow ROW1 = sheet.createRow (0); 
        HSSFCell cell row1.createCell = (0); 
        // set value, the cell corresponding to the title incorporated herein 
        cell.setCellValue ( "personnel information table") ; 
        // Add style commencement 
        cell.setCellStyle (style); 

        for (int I = 0; I <userList.size (); I ++) { 
            // row 
            HSSFRow sheet.createRow row = (I +. 1); 
            // for assignment column
            row.createCell(0).setCellValue(userList.get(i).getId());
            row.createCell(1).setCellValue(userList.get(i).getName());
            row.createCell(2).setCellValue(userList.get(i).getPassword());
            row.createCell(3).setCellValue(userList.get(i).getRemark());
        }
        workbook.write(outputStream);
        outputStream.close();
    }


}

In the TestController

3. Test

Visit: http: // localhost: 8080 / ssm2 / test

In the disc D will generate a file open as follows test.xls

 

two. Exported from the database to excel

 1. Preparation POIUtil Tools

public static List<User> importExcel() throws Exception{
        HSSFWorkbook workbook = new HSSFWorkbook(new FileInputStream(new File("D:\\t1.xls")));
        HSSFSheet sheet = null;

        for(int i = 0;i < workbook.getNumberOfSheets();i++){
            //获取每个sheet
            sheet = workbook.getSheetAt(i);
            List<User> list = new ArrayList<User>();
            //getPhysicalNumberOfRows获取有记录的行数
            for(int j = 0;j < sheet.getPhysicalNumberOfRows();j++){
                Row row = sheet.getRow(j);
                if(null!=row){
                    //getLastCellNum获取最后一列
                    User user = new User();
                    for(int k = 0;k < row.getLastCellNum();k++){
                        if(null!=row.getCell(k)){
                            if(k==0){
                                Cell cell = row.getCell(0);
                                //cell->double
                                Double d = cell.getNumericCellValue();
                                //double->int
                                int id = new Double(d).intValue();
                                user.setId(id);
                            }
                            if(k==1){
                                Cell cell = row.getCell(1);
                                //cell->string
                                user.setName(cell.getStringCellValue().toString());
                            }
                            if(k==2){
                                Cell cell = row.getCell(2);
                                user.setPassword(cell.getStringCellValue().toString());
                            }
                            if(k==3){
                                Cell cell = row.getCell(3);
                                user.setRemark(cell.getStringCellValue().toString());
                            }
                        }

                    }
                    list.add(user);


                }

            }
            System.out.println("读取sheet表："+ workbook.getSheetName(i) + "完成");
            return list;
        }

        return null;
    }

At the time of writing tools of the problems encountered Summary:

(1)getLastRowNum  

    If the sheet does not have a row of data is -1, only the first line of data is returned to 0, is the last data row n-1 n-th row is returned;

    getPhysicalNumberOfRows  

    Get the number of recorded lines, namely: the last data line has n-th row, m-th row in front of the line is not blank data, then returns nm;

Prior written getLastRowNum () to perform row.getLastCellNum () = - 1, to obtain the value of less than excel

(2) How to assign a value to an object in the loop, if I wrote a judgment

(3)cell->int和string

2.UserMapper.xml

<insert id="insertData" parameterType="list">
    insert into user(id,name,password,remark) VALUES
    <foreach collection="list" index="index" item="user" separator=",">
      (#{user.id},#{user.name},#{user.password},#{user.remark})
    </foreach>
  </insert>

3.UserMapper and interfaces as UserService

int insertData(List<User> users);

4.UserServiceImpl

@Override
    public int insertData(List<User> users) {
        int num = userMapper.insertData(users);
        return num;
    }

5.TestController

@RequestMapping("/insertData")
    public void insertData() throws Exception{
        List<User> users = POIUtil.importExcel();
        int num = userService.insertData(users);
        if(num > 0){
            System.out.println("插入数据成功");
        }

    }

excel data D: /t1.xls, the following data

6. Test

访问：http://localhost:8080/ssm2/insertData

 That view in the database as success:

 Note: This article simply wrote under POI import and export functions, of course, there are many uses yet to be learning the POI.

Reproduced in: https: //www.cnblogs.com/xinyijiu/p/10969690.html