java 导出Excel 使用apache POI.jar 包

小乔

　　使用Java Annotation写Excel 工具类

package com.excel.export.util;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
*
* <p>导出excel 工具包</p>
* @author liuqing
* @version 1.0
* @see 导出excel 注解
*
*/
@Retention(value=RetentionPolicy.RUNTIME)
@Target(value=ElementType.FIELD)
public @interface AllowExcel {
boolean value() default true;
String name();
}

　　写实现类

package com.excel.export.util;
import java.io.Serializable;
import java.util.Date;
/**
*
* @author liuqing
* @version 1.0
* @datetime 2011-11-24
* @see 学生测试对象
*
*/
public class Student implements Serializable {
private static final long serialVersionUID = -8141916472359874289L;
@AllowExcel(name="编号")
private Integer id;
@AllowExcel(name="姓名")
private String name;
@AllowExcel(name="生日")
private Date date;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
}

　　POI 实现类

package com.cxxx.common;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
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;
/**
*
* @author LiuQing
* @see excel 导出工具类
* 使用方法
* class EntityObjectClass {
*
*      @AllowExcel(name="姓名")
* private String name;
*
*      @AllowExcel(name="生日")
*      private Date birthday
*
* }
*
* ExportExcel<EntityObjectClass> export = new ExportExcel<EntityObjectClass>();
* List<EntityObjectClass> data = new ArrayList<EntityObjectClass>();
* InputStream inputStream = export.createExcel(data);
*
* @version 1.0
* @datetime 2011-11-24
*
*/
public class ExportExcel<T extends Serializable> {
/**
* 定义Excel hander
*/
private Workbook excelHander = new HSSFWorkbook();
/**
* 生成sheet 名称
*/
private String sheetName = "sName";
private boolean showHeader = true;
private Collection<T> tempData = new ArrayList<T>();
private boolean isFirst = true;
/**
* 缓存成员变量
*/
private List<String> fieldNameCaches = new ArrayList<String>();
/**
* @see 生成Excel 文件
* @param data
* @return
* @throws IllegalAccessException
*/
public InputStream createExcel(Collection<T> data) throws Exception {
this.tempData = data;
this.createHeader(data);
return this.getInputStream();
}
public void addDate(T t) throws Exception {
this.tempData.add(t);
}
/**
*
* @return
* @throws Exception
*/
public InputStream createExcel() throws Exception {
this.createHeader(this.tempData);
return this.getInputStream();
}
/**
* 创建器
* @param data
* @throws IllegalAccessException
*/
private void createHeader(Collection<T> data) throws Exception {
//Sheet 创建工作表
Sheet sheet = excelHander.createSheet(sheetName);
int j = 0;
for (T t:data) {
Field[] fields = t.getClass().getDeclaredFields();
/**
* 加入允许字段缓存数据
* if == 0时表示要添加缓存数据
*/
if (j == 0) {
Row headRow = null;
if (this.showHeader) {
headRow = sheet.createRow(0);
}
int i = 0;
for (Field field:fields) {
//判断Excel 安全允许注解
AllowExcel allowExcel = field.getAnnotation(AllowExcel.class);
if (allowExcel != null && allowExcel.value()) {
//显示关部信息
if (this.showHeader) {
Cell cell = headRow.createCell(i);
cell.setCellValue(allowExcel.name());
i++;
}
this.fieldNameCaches.add(field.getName());
}
}
j++;
}
//创建产生行数据
Row hssfRow = sheet.createRow(j);
this.setCellValueToRow(t, hssfRow);
j++;
}
}
/**
* 输出Excel Row 信息
* @param t T extends Serializable
* @param hssfRow HSSFRow
* @return HSSFRow
* @throws IllegalAccessException
* @throws NoSuchMethodException
* @throws SecurityException
*/
public Row setCellValueToRow(T t,Row hssfRow) throws Exception {
Class clazz = t.getClass();
Field fields[] = clazz.getDeclaredFields();
//定义Excel 输出行数
int i = 0;
for (Field field:fields) {
//缓存中是否存在允许字段
if (this.isCacheFiledName(field.getName())) {
Cell cell = hssfRow.createCell(i);
i++;
field.setAccessible(true);
Class clazzType = field.getType();
String methodName = "";
if (clazzType.getName().equals("boolean") ||
clazzType.getName().equals("java.lang.Boolean")) {
methodName = "is" + this.toFirstToUp(field.getName());
}
else {
methodName = "get" + this.toFirstToUp(field.getName());
}
Object obj = clazz.getMethod(methodName, null).invoke(t, null);
//Object obj = clazz.getDeclaredMethod(methodName, null).invoke(t, null);
//类型转换
if (obj instanceof Integer ) {
cell.setCellValue((Integer)obj);
}
else if (obj instanceof String) {
cell.setCellValue((String)obj);
}
else if (obj instanceof Date) {
cell.setCellValue((Date)obj);
}
else if (obj instanceof Double) {
cell.setCellValue((Double)obj);
}
else if (obj instanceof Boolean) {
cell.setCellValue((Boolean)obj);
}
else if (obj instanceof Float) {
cell.setCellValue((Float)obj);
}
else if (obj instanceof Long) {
cell.setCellValue((Long)obj);
}
else {
System.out.println(obj);
//throw new TypeNotPresentException("类型不支持", null);
}
}
}
return hssfRow;
}
/**
* 判断Cache 是否有对应的FiledName
* @param fieldName String
* @return boolean
*/
private boolean isCacheFiledName(String fieldName) {
if (fieldName == null) {
return false;
}
for (String fieldNameCache:this.fieldNameCaches) {
if (fieldName.equals(fieldNameCache)) {
return true;
}
}
return false;
}
/**
* 获得输入流
* @return InputStream
*/
private InputStream getInputStream() {
ByteArrayOutputStream output = new ByteArrayOutputStream();
InputStream inputStream = null;
try {
this.excelHander.write(output);
byte b[] = output.toByteArray();
inputStream = new ByteArrayInputStream(b);
}
catch (IOException e) {
e.printStackTrace();
}
finally {
try {
output.flush();
output.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
return inputStream;
}
/**
* 查找对应的类自定义方法
* @param methodName
* @return boolean
*/
public boolean isClassMethodName(String methodName) {
if (methodName != null) {
if ("getClass".equals(methodName)) {
return false;
}
if (methodName.startsWith("get")
|| methodName.startsWith("is")
|| methodName.startsWith("set")) {
return true;
}
return false;
}
return false;
}
/**
*
* @param str
* @return String
*/
public static String toFirstToLower(String str) {
char chars[] = str.toCharArray();
if (chars != null && chars.length > 0) {
if (chars[0] > 'A') {
chars[0] = (char) (chars[0] + 32);
}
}
return new String(chars);
}
/**
* 首字母转为大写
* @param str String
* @return String
*/
public static String toFirstToUp(String str) {
char chars[] = str.toCharArray();
if (chars != null && chars.length > 0) {
if (chars[0] >= 'a') {
chars[0] = (char) (chars[0] - 32);
}
}
return new String(chars);
}
}