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java 利用 poi 生成 Excel文件的例子

在用java 写数据库应用的时候, 通常会生成各种报表,而这些报表可能会被导出为各种格式的文件,比如Excel文档,pdf 文档等等. 今天先做了一个生成Excel 文档的例子,主要解决以下问题:
1. 生成 Excel 文档.
2. 保护生成Excel文档,设置密码访问.
3. 自动对生成的Excel 文档第一行标题栏设置成filter 过滤形式, 方便用户使用.

用 apache  POI 生成 Excel 文档公用类 
程序代码 程序代码

package com.yihaomen.poi.sample;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;


/**
* Excel util, create excel sheet, cell and style.
* @param <T> generic class.
*/
public class ExcelUtil<T> {
   
    public HSSFCellStyle getCellStyle(HSSFWorkbook workbook,boolean isHeader){
        HSSFCellStyle style = workbook.createCellStyle();
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
        style.setBorderRight(HSSFCellStyle.BORDER_THIN);
        style.setBorderTop(HSSFCellStyle.BORDER_THIN);
        style.setLocked(true);
        if (isHeader) {
            style.setFillForegroundColor(HSSFColor.GREY_25_PERCENT.index);
            style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
            HSSFFont font = workbook.createFont();
            font.setColor(HSSFColor.BLACK.index);
            font.setFontHeightInPoints((short) 12);
            font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
            style.setFont(font);
        }        
        return style;
    }
    
   
    public  void generateHeader(HSSFWorkbook workbook,HSSFSheet sheet,String[] headerColumns){
        HSSFCellStyle style = getCellStyle(workbook,true);
        Row row = sheet.createRow(0);
        row.setHeightInPoints(30);
        for(int i=0;i<headerColumns.length;i++){
            Cell cell = row.createCell(i);
            String[] column = headerColumns[i].split("_#_");
            sheet.setColumnWidth(i, Integer.valueOf(column[1]));
            cell.setCellValue(column[0]);
            cell.setCellStyle(style);
        }
    }    
    
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public  HSSFSheet creatAuditSheet(HSSFWorkbook workbook,String sheetName,
            List<T> dataset,String[] headerColumns,String[] fieldColumns) throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        
        HSSFSheet sheet = workbook.createSheet(sheetName);
        sheet.protectSheet("");
        
        generateHeader(workbook,sheet,headerColumns); 
        HSSFCellStyle style = getCellStyle(workbook,false);
        SimpleDateFormat sd = new SimpleDateFormat("yyyy-MM-dd");
        int rowNum = 0;
        for(T t:dataset){
            rowNum++ ;
            Row row = sheet.createRow(rowNum); 
            row.setHeightInPoints(25);
            for(int i = 0; i < fieldColumns.length; i++){               
                String fieldName = fieldColumns[i] ;              
               
                String getMethodName = "get" + fieldName.substring(0,1).toUpperCase() + fieldName.substring(1);                   
                try {                    
                    Class clazz = t.getClass();
                    Method getMethod;
                    getMethod = clazz.getMethod(getMethodName, new Class[]{} );
                    Object value = http://www.mamicode.com/getMethod.invoke(t, new Object[]{});
                    String cellValue = http://www.mamicode.com/"";
                    if (value instanceof Date){
                        Date date = (Date)value;
                        cellValue = http://www.mamicode.com/sd.format(date);
                    }else{ 
                        cellValue = http://www.mamicode.com/null != value ? value.toString() : "";
                    }                    
                    Cell cell = row.createCell(i);
                    cell.setCellStyle(style);
                    cell.setCellValue(cellValue);
                   
                } catch (Exception e) {
                    
                } 
            }            
        }
        return sheet;        
    }

}


这一个公用的类,主要生成Excel的头,正文,以及Excel 文档的样式。看方法名称基本就可以知道这个方法是干什么用的.

写一个测试类测试生成Excel文档 
程序代码 程序代码

package com.yihaomen.poi.test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import com.yihaomen.poi.sample.ExcelUtil;
import com.yihaomen.poi.sample.User;

public class PoiTest {
    
     /*excel column formate:column_#_width, excel中每一列的名称*/
    public static final String[] USER_RECORES_COLUMNS = new String[]{
            "User Name_#_3000",
            "Address_#_7000"           
            };
    /*the column will display on xls files. must the same as the entity fields.对应上面的字段.*/
    public static final String[] USER_RECORES_FIELDS = new String[]{
        "name","address"
    };
    
    public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, IOException {
        List<User> users = new ArrayList<User>();
        for(int i=0; i<10;i++){
            User u = new User();
            u.setAddress("address :" + i);
            u.setName("name: "+ i);
            u.setAge(i);
            users.add(u);
        }
        
        //实际项目中,这个list 估计是从数据库中得到的
        
        HSSFWorkbook workbook = new HSSFWorkbook();
        ExcelUtil<User> userSheet = new ExcelUtil<User>();
        userSheet.creatAuditSheet(workbook, "user sheet xls", 
                users, USER_RECORES_COLUMNS, USER_RECORES_FIELDS);
        
        FileOutputStream fileOut = new FileOutputStream("d:/yihaomen_user_test.xls"); 
        workbook.write(fileOut); 
        fileOut.close(); 
    }

}


这里直接保存文件到 D 盘下面,主要是为了自己测试方便. 另外还需要一个测试需要的实体类 User.java:
程序代码 程序代码

package com.yihaomen.poi.sample;

public class User {
    
    private String name;
    private int age;
    private String address;
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
}



运行测试类,生成Excel 文档如下:


生成的文档,你是不能修改的,原因很简单,设置了一个空密码,虽然是空密码,Excel 还是会出现提示,当然你可以直接解保护. 实现的主要代码是在 ExcelUtil 中的 creatAuditSheet 方法中的:
程序代码 程序代码

sheet.protectSheet(""); // 设置了一个空的密码


如果要实现第一行标题自动过滤怎么处理呢,可以在上面提到的方法中加入如下代码:
程序代码 程序代码

char[] endChar = Character.toChars( ‘A‘ + (headerColumns.length - 1) );        
String rangeAddress = "A1:" + String.valueOf(endChar) + "1";
sheet.setAutoFilter(CellRangeAddress.valueOf(rangeAddress));

java 利用 poi 生成 Excel文件的例子