利用注解和POI导入Excel

声明：前段时间，我在开源中国码云上面，看到项目jeesite中导入Excel是利用注解来操作，加上之前我在工作中也有批量处理导入Excel的功能，但是没有使用注解，代码不简洁。所以，借鉴这种方式，自己又码一遍代码，不算原创。

先了解下，java注解，这是为博客园的帖子：http://www.cnblogs.com/peida/archive/2013/04/24/3036689.html

因此定义以下注解：

@Target({ElementType.METHOD,ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelField {
	int sort() default 0;
}

Excel工具类

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import poi.demo.annotation.ExcelField;

public class ExcelUtil {
	
	private Workbook wb;
	
	private Sheet sheet;
	
	private int headerNum;//标题行号
	
	public ExcelUtil(String fileName, int headerNum, int sheetIndex) throws FileNotFoundException, IOException{
		this(new File(fileName), headerNum, sheetIndex);
		
	}
	
	public ExcelUtil(File file, int headerNum, int sheetIndex) throws FileNotFoundException, IOException {
		this(file.getName(), new FileInputStream(file), headerNum, sheetIndex);
		
	}

	public ExcelUtil(String fileName, InputStream is, int headerNum, int sheetIndex) throws IOException {
		// TODO Auto-generated constructor stub
		if(fileName.toLowerCase().endsWith("xls")){    
			this.wb = new HSSFWorkbook(is);    
        }else if(fileName.toLowerCase().endsWith("xlsx")){  
        	this.wb = new XSSFWorkbook(is);
        }else{  
        	throw new RuntimeException("文档格式不正确!");
        }  
		this.sheet= this.wb.getSheetAt(sheetIndex);
		this.headerNum=headerNum;
	}

	/**
	 *@title getDataList
	 *@description 获取转化后的Excel数据列表
	 *@param clazz
	 *@return
	 *@throws InstantiationException
	 *@throws IllegalAccessException List<E>
	 */
	public <E> List<E> getDataList(Class<E> clazz) throws InstantiationException, IllegalAccessException{
		List<Object[]> annotationList = new ArrayList<Object[]>();
		//获取带有注解的属性
		Field[] fs = clazz.getDeclaredFields();
		for(Field f : fs){
			ExcelField ef = f.getAnnotation(ExcelField.class);
			if(ef != null){
				annotationList.add(new Object[]{ef,f});
			}
		}
		//排序
		Collections.sort(annotationList, new Comparator<Object[]>() {
			public int compare(Object[] o1, Object[] o2) {
				return new Integer(((ExcelField)o1[0]).sort()).compareTo(new Integer(((ExcelField)o2[0]).sort()));
			}
		});
		
		List<E> dataList = new ArrayList<E>();
		
		for(int i=this.getDataRowNum();i<=this.getLastDataRowNum();i++){
			E e = (E)clazz.newInstance();
			int column = 0;
			Row row = this.getRow(i);
			for(Object[] obj : annotationList){
				Object val = this.getCellValue(row, column++);
				if(val != null){
					@SuppressWarnings("unused")
					ExcelField ef = (ExcelField)obj[0];
					if(obj[1] instanceof Field){
						ReflectionUtils.invokeSetter(e, ((Field)obj[1]).getName(), val);
					}
				}
			}
			dataList.add(e);
		}
		return dataList;
	}
	
	/**
	 *@title getRow
	 *@description 获取行数据
	 *@param rowNum
	 *@return Row
	 */
	public Row getRow(int rowNum){
		return this.sheet.getRow(rowNum);
		
	}
	/**
	 *@title getDataRowNum
	 *@description 获取数据行号
	 *@return int
	 */
	public int getDataRowNum(){
		return this.headerNum+1;
	}
	
	/**
	 *@title getLastDataRowNum
	 *@description 获取数据最后一行行号
	 *@return int
	 */
	public int getLastDataRowNum(){
		return this.sheet.getLastRowNum()+headerNum;
	}
	
	/**
	 *@title getCellValue
	 *@description 获取单元格的值
	 *@param row
	 *@param column
	 *@return Object
	 */
	public Object getCellValue(Row row, int column){
		Object val = "";
		try{
			Cell cell = row.getCell(column);
			if (cell != null){
				if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC){
					val = cell.getNumericCellValue();
				}else if (cell.getCellType() == Cell.CELL_TYPE_STRING){
					val = cell.getStringCellValue();
				}else if (cell.getCellType() == Cell.CELL_TYPE_FORMULA){
					val = cell.getCellFormula();
				}else if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN){
					val = cell.getBooleanCellValue();
				}else if (cell.getCellType() == Cell.CELL_TYPE_ERROR){
					val = cell.getErrorCellValue();
				}
			}
		}catch (Exception e) {
			return val;
		}
		return val;	
		
	}

	public Workbook getWb() {
		return wb;
	}

	public void setWb(Workbook wb) {
		this.wb = wb;
	}

	public Sheet getSheet() {
		return sheet;
	}

	public void setSheet(Sheet sheet) {
		this.sheet = sheet;
	}

	public int getHeaderNum() {
		return headerNum;
	}

	public void setHeaderNum(int headerNum) {
		this.headerNum = headerNum;
	}

}

反射工具类

package poi.demo;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;

public class ReflectionUtils {
	
	private static final String SETTER_PREFIX = "set";

	private static final String GETTER_PREFIX = "get";
	
	/**
	 *@title invokeSetter
	 *@description 调用Setter方法, 仅匹配方法名。
	 * 支持多级，如：对象名.对象名.方法
	 *@param obj
	 *@param propertyName
	 *@param value void
	 */
	public static void invokeSetter(Object obj, String propertyName, Object value){
		Object object = obj;
		String[] names = StringUtils.split(propertyName, ".");
		for (int i=0; i<names.length; i++){
			if(i<names.length-1){
				String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(names[i]);
				object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});
			}else{
				String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(names[i]);
				invokeMethodByName(object, setterMethodName, new Object[] { value });
			}
		}
	}
	
	public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes,
			final Object[] args) {
		Method method = getAccessibleMethod(obj, methodName, parameterTypes);
		if (method == null) {
			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
		}

		try {
			return method.invoke(obj, args);
		} catch (Exception e) {
			//throw new convertReflectionExceptionToUnchecked(e);
		}
		return null;
	}

	/**
	 * 直接调用对象方法, 无视private/protected修饰符，
	 * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
	 * 只匹配函数名，如果有多个同名函数调用第一个。
	 */
	public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {
		Method method = getAccessibleMethodByName(obj, methodName);
		if (method == null) {
			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
		}

		try {
			return method.invoke(obj, args);
		} catch (Exception e) {
			//throw convertReflectionExceptionToUnchecked(e);
		}
		return null;
	}
	
	public static Method getAccessibleMethod(final Object obj, final String methodName,
			final Class<?>... parameterTypes) {
		//Validate.notNull(obj, "object can't be null");
		//Validate.notBlank(methodName, "methodName can't be blank");

		for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
			try {
				Method method = searchType.getDeclaredMethod(methodName, parameterTypes);
				makeAccessible(method);
				return method;
			} catch (NoSuchMethodException e) {
				// Method不在当前类定义,继续向上转型
				continue;// new add
			}
		}
		return null;
	}
	
	public static Method getAccessibleMethodByName(final Object obj, final String methodName) {
		Validate.notNull(obj, "object can't be null");
		Validate.notBlank(methodName, "methodName can't be blank");

		for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
			Method[] methods = searchType.getDeclaredMethods();
			for (Method method : methods) {
				if (method.getName().equals(methodName)) {
					makeAccessible(method);
					return method;
				}
			}
		}
		return null;
	}
	
	public static void makeAccessible(Method method) {
		if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))
				&& !method.isAccessible()) {
			method.setAccessible(true);
		}
	}
	
	public static void makeAccessible(Field field) {
		if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier
				.isFinal(field.getModifiers())) && !field.isAccessible()) {
			field.setAccessible(true);
		}
	}
}

例子：

import poi.demo.annotation.ExcelField;

public class People {
	@ExcelField(sort=0)
	private String name;
	@ExcelField(sort=1)
	private String sex;
	@ExcelField(sort=2)
	private String color;
	
	private int age;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex = sex;
	}

	public String getColor() {
		return color;
	}

	public void setColor(String color) {
		this.color = color;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}
	
}

测试用例：

package poi.demo;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import poi.demo.annotation.ExcelField;

public class ImportTest {

	public static void main(String[] args) throws FileNotFoundException, IOException, InstantiationException, IllegalAccessException {
		ExcelUtil ex = new ExcelUtil("D://test.xlsx",0,0);
		
		List<People> list = ex.getDataList(People.class);
		for(People p : list){
			//业务代码		   System.out.println(p.getName()+"是"+p.getColor()+"人，性别为"+p.getSex());
		}
	}

}