poi excel

 

 

 

package com.tch.test.t1;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class ExportExcel {
	private static SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	/**
	 * 
	 *  Created on 2013-4-3 
	 * <p>Discription:导出excel工具方法</p>
	 * @param file 导出目标文件 source 导出的数据源  columnNames每列的名字
	 * @param fieldNames 属性名 className 类名
	 * @author:
	 * @update:[日期YYYY-MM-DD] [更改人姓名]
	 * @return void
	 */
	public static byte[] exportExcel(List<?> source,String[] columnNames,String[] fieldNames){
		byte[] b = null;
		if(source == null || columnNames == null || fieldNames == null){
			return b;
		}
		if(columnNames.length != fieldNames.length){
			return b;
		}
        HSSFWorkbook hwb = new HSSFWorkbook();  
        HSSFCell hc = null;  
        HSSFRow hr = null;  
        HSSFSheet hs = null;  
        HSSFCellStyle cellStyle = hwb.createCellStyle();  
        HSSFFont cellFont = hwb.createFont();  
        cellStyle.setFont(cellFont);  
        hs = hwb.createSheet();  
        hr = hs.createRow((short) 0);  
        int length = columnNames.length;
        /**
         * 设置excel的表头
         */
        for(int i=0;i<length;i++){
        	hc = hr.createCell((short)i); 
        	hc.setEncoding(HSSFCell.ENCODING_UTF_16);
        	hc.setCellValue(columnNames[i]);
        }
        String[] result = null;
        for(int i=0;i<source.size();i++){
        	result = ObjectToArray(source.get(i),fieldNames);
        	if(result == null || result.length == 0 || length != result.length){
        		break;
        	}
        	hr = hs.createRow((short) (i+1));
        	for(int j=0;j<length;j++){
            	hc = hr.createCell((short)j); 
            	hc.setEncoding(HSSFCell.ENCODING_UTF_16);
            	hc.setCellValue(result[j]);
            }
        }
        try {
        	ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
			hwb.write(outputStream);
			b = outputStream.toByteArray();
		} catch (IOException e) {
			e.printStackTrace();
		} 
		return b;
	}
	
	/**
	 * 
	 *  Created on 2013-4-3 
	 * <p>Discription:把属性值按照给定的属性的顺序存储到数组里面返回</br>
	 * 例如：User,给定的属性名为username,password,ipAddress</br>
	 * 则返回的数组为对应的username，password,ipAddress的值</p>
	 * @author:
	 * @update:[日期YYYY-MM-DD] [更改人姓名]
	 * @return String[]
	 */
	@SuppressWarnings("unchecked")
	public static String[] ObjectToArray(Object model,String[] fieldNames) {
		String[] result = new String[fieldNames.length];
		try {
			Class clazz = model.getClass();
//			Field field = null;
			Type type = null;
			Method method= null;
			String property = null;
			boolean isComplexType = false;
			String complexFieldName = null;
			for(int i=0;i<fieldNames.length;i++){
				isComplexType = false;
				property = fieldNames[i];
				if(property.contains(".")){    //包含" . " 说明是复杂类型
					int index = property.indexOf(".");
					isComplexType = true;
					complexFieldName = property.substring(index+1);
					property = property.substring(0, index);
				}
//				field = clazz.getDeclaredField(property);
//				System.out.println("attribute name:"+property);  
//				type = field.getGenericType();
//				System.out.println("Generictype name:"+type.toString()+"   type:  "+field.getType());  
				method = clazz.getMethod("get"+property.substring(0, 1).toUpperCase()+property.substring(1, property.length()));
				if(method != null){
					if(isComplexType){
						result[i] = ObjectToArray(method.invoke(model), new String[]{complexFieldName})[0];
					}else{
						if(type != null && "class java.util.Date".equals(type.toString())){
							result[i] = String.valueOf(formatDate((Date)method.invoke(model)));
						}else{
							result[i] = String.valueOf(method.invoke(model));
						}System.out.println(result[i]);						
					}
					
				}
			}
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		}
		return result;
	}

	private static String formatDate(Date date) {
		return format.format(date);
	}
}