Java反射使用自定义注解@Excel导出Excel
一、新建注解@Excel
package annotation; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) public @interface Excel { /** * 表头名字 */ String name() default ""; /** * 列顺序 */ int sort() default Integer.MAX_VALUE; /** * 日期格式化 */ String pattern() default "yyyy-MM-dd"; /** * 列宽度 */ double width() default 16; /** * 默认值 */ String defaultValue() default ""; /** * 对齐方式 */ Align align() default Align.CENTER; /** * 码值转换 * 替换类型 {"0_女", "1_男"} */ String[] codeValue() default {}; enum Align { AUTO(0), LEFT(1), CENTER(2), RIGHT(3); private final int value; Align(int value) { this.value = value; } public int value() { return this.value; } } }
二、新建工具类ExportExcelUtil
package utils;
import annotation.Excel;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.collections4.ListUtils;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFPalette;
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.*;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;
import java.util.stream.Collectors;
import static org.apache.commons.lang3.StringUtils.isBlank;
import static org.apache.commons.lang3.StringUtils.isNotBlank;
public class ExportExcelUtil {
private static HSSFWorkbook workbook;
private static HSSFCellStyle leftStyle;
private static HSSFCellStyle rightStyle;
private static HSSFCellStyle centerStyle;
private static HSSFCellStyle defaultTitleStyle;
//取色板
private static HSSFPalette palette;
private static final int sheetSize = 65535;
private static Map<String, Object> codeMap = new HashMap<>();
/***
*
* @param list 导出数据集合
* @param sheetName 工作表名称
* @param clazz 实体对象
* @return
* @throws InvocationTargetException
* @throws IllegalAccessException
* @throws IOException
*/
public static InputStream export(List<?> list, String sheetName, Class<?> clazz) throws InvocationTargetException, IllegalAccessException, IOException {
if (list == null) {
list = new ArrayList<>();
}
handleSheetName(sheetName);
workbook = new HSSFWorkbook();
leftStyle = workbook.createCellStyle();
rightStyle = workbook.createCellStyle();
centerStyle = workbook.createCellStyle();
defaultTitleStyle = workbook.createCellStyle();
palette = workbook.getCustomPalette();
Field[] fields = clazz.getDeclaredFields();
List<Field> fieldsList = Arrays.stream(fields).filter(f -> f.isAnnotationPresent(Excel.class)).sorted(Comparator.comparing(c -> {
Excel annotation = c.getAnnotation(Excel.class);
return annotation.sort();
})).collect(Collectors.toList());
Map<String, Method> methods = ExportExcelUtil.getMethod(clazz, fieldsList, "get");
List<? extends List<?>> partitionList = ListUtils.partition(list, sheetSize);
if (CollectionUtils.isEmpty(partitionList)) {
HSSFSheet sheet = workbook.createSheet(sheetName);
createTitleRow(fieldsList, sheet);
}
for (int sheetNum = 0; sheetNum < partitionList.size(); sheetNum ++) {
String presentName = sheetName + (sheetNum + 1);
if (partitionList.size() == 1) {
presentName = sheetName;
}
HSSFSheet sheet = workbook.createSheet(presentName);
// 创建标题行
createTitleRow(fieldsList, sheet);
// 创建普通行
for (int i = 0; i < partitionList.get(sheetNum).size(); i++) {
Row sheetRow = sheet.createRow(i + 1);
sheetRow.setHeight((short) (16 * 20));
Object targetObj = partitionList.get(sheetNum).get(i);
int cellIndex = 0;
for (int j = 0; j < fieldsList.size(); j++, ++cellIndex) {
Field field = fieldsList.get(j);
Method method = methods.get(field.getName());
Object value = method.invoke(targetObj);
Excel annotation = field.getAnnotation(Excel.class);
// 处理默认值
if (null == value) {
if (isNotBlank(annotation.defaultValue())) {
value = annotation.defaultValue();
} else {
value = "";
}
}
// 转换日期格式
if (isNotBlank(annotation.pattern()) && field.getType().equals(Date.class) && isNotBlank(String.valueOf(value))) {
}
// 码值转换
if (annotation.codeValue().length > 0 && isNotBlank(String.valueOf(value))) {
value = replaceCode(annotation.codeValue(), String.valueOf(value), field.getName());
}
ExportExcelUtil.setCellValues(sheetRow, cellIndex, value, annotation);
}
}
}
ByteArrayOutputStream os = new ByteArrayOutputStream();
workbook.write(os);
os.flush();
os.close();
workbook.close();
return new ByteArrayInputStream(os.toByteArray());
}
private static void createTitleRow(List<Field> fieldsList, HSSFSheet sheet) {
Row titleRow = sheet.createRow(0);
for (int i = 0; i < fieldsList.size(); i++) {
Excel annotation = fieldsList.get(i).getAnnotation(Excel.class);
ExportExcelUtil.setCellValues(titleRow, i, annotation.name(), annotation);
// 设置列宽
double width = annotation.width();
if (width * 256 > 65280) {
width = 255;
}
titleRow.setHeightInPoints(18);
titleRow.setHeight((short) (18 * 20));
sheet.setColumnWidth(i, (int) (width * 256));
}
}
private static void setCellValues(Row row, Integer currentIndex, Object value, Excel annotation) {
Cell cell = row.createCell(currentIndex);
// 第一行
if (row.getRowNum() == 0) {
cell.setCellStyle(getTitleDefaultStyle());
} else {
// 默认样式
if (annotation.align() == Excel.Align.LEFT) {
cell.setCellStyle(getAlignLeftCellStyle());
} else if (annotation.align() == Excel.Align.RIGHT) {
cell.setCellStyle(getAlignRightCellStyle());
} else {
cell.setCellStyle(getDefaultCellStyle());
}
}
cell.setCellValue(value.toString());
}
private static Map<String, Method> getMethod(Class<?> clazz, List<Field> fieldsList, String methodKeyWord) {
Map<String, Method> methodMap = new HashMap<String, Method>();
/* 获取类模板所有属性 */
for (Field value : fieldsList) {
/* 获取属性名并组装方法名称 */
String fieldName = value.getName();
/*
* methodKeyWord = 'get'
* fieldName = 'name'
* fieldName.substring(0, 1).toUpperCase() = 'N'
* fieldName.substring(1) = 'ame()'
* getMethodName = 'getName()'
* */
String getMethodName = methodKeyWord +
fieldName.substring(0, 1).toUpperCase() +
fieldName.substring(1);
try {
Method method = clazz.getMethod(getMethodName);
/*
* 存储内容为: id,getId();
* name,getName();
* */
methodMap.put(fieldName, method);
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
}
return methodMap;
}
/**
* 码值替换
*/
private static String replaceCode(String[] codeValue, String value, String field) {
if (!codeMap.containsKey(field)) {
List<Map<String, String>> codeList = Arrays.stream(codeValue).filter(f -> isNotBlank(f) && f.contains("_")).map(code -> {
String[] codeAndValue = code.split("_");
Map<String, String> codeMap = new HashMap<String, String>() {{
put(codeAndValue[0], codeAndValue[1]);
}};
return codeMap;
}).collect(Collectors.toList());
codeMap.put(field, codeList);
}
List<Map<String, String>> currCodeList = (List<Map<String, String>>) codeMap.get(field);
for (Map<String, String> codeMap : currCodeList) {
if (codeMap.containsKey(value)) {
return codeMap.get(value);
}
}
return value;
}
private static String handleSheetName(String sheetName) {
if (isBlank(sheetName)) {
sheetName = "Sheet";
}
sheetName = sheetName.replaceAll("[\\s\\\\/:\\*\\?\\\"<>\\|]", "");
if (sheetName.length() > 30) {
sheetName = sheetName.substring(0, 30);
}
return sheetName;
}
/**
* 默认的cell样式，垂直居中
*
* @return
*/
private static HSSFCellStyle setBaseCellStyle(HSSFCellStyle style) {
style.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
// style.setBorderBottom(BorderStyle.THIN); //下边框
// style.setBorderLeft(BorderStyle.THIN);//左边框
// style.setBorderTop(BorderStyle.THIN);//上边框
// style.setBorderRight(BorderStyle.THIN);//右边框
return style;
}
private static HSSFCellStyle getDefaultCellStyle() {
centerStyle.setAlignment(HorizontalAlignment.CENTER);//水平居中
setBaseCellStyle(centerStyle);
return centerStyle;
}
private static HSSFCellStyle getAlignLeftCellStyle() {
leftStyle.setAlignment(HorizontalAlignment.LEFT);//水平居中
leftStyle.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
setBaseCellStyle(leftStyle);
return leftStyle;
}
private static HSSFCellStyle getAlignRightCellStyle() {
rightStyle.setAlignment(HorizontalAlignment.RIGHT);//水平居中
rightStyle.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
setBaseCellStyle(rightStyle);
return rightStyle;
}
/**
* 默认标题样式
*/
private static HSSFCellStyle getTitleDefaultStyle() {
Font f = workbook.createFont();
f.setFontHeightInPoints((short) 11);
f.setBold(true);// 加粗
f.setFontName("宋体");
f.setColor((short) 9);
defaultTitleStyle.setFont(f);
defaultTitleStyle.setBorderBottom(BorderStyle.THIN); //下边框
defaultTitleStyle.setBorderLeft(BorderStyle.THIN);//左边框
defaultTitleStyle.setBorderTop(BorderStyle.THIN);//上边框
defaultTitleStyle.setBorderRight(BorderStyle.THIN);//右边框
//设置颜色
HSSFColor hssfColor = palette.findSimilarColor(140, 130, 130);
defaultTitleStyle.setFillForegroundColor(hssfColor.getIndex());
defaultTitleStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
defaultTitleStyle.setAlignment(HorizontalAlignment.CENTER);//水平居中
defaultTitleStyle.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
setBaseCellStyle(defaultTitleStyle);
return defaultTitleStyle;
}
}三、代码已提交至Github
https://github.com/LiuFqiang/export-excel.git
生成的Excel如下
