Cenário de negócios: o botão de exportação de uma página, porque há muitos campos e o cliente deseja exportar campos diferentes para facilitar a observação a cada vez, por isso é necessário selecionar dinamicamente a coluna de exportação do Excel
Índice
自定义注解 + POI O método adotado neste artigo é usado para realizar
sem mais delongas, vamos ver o efeito primeiro, se não atender o seu efeito, basta excluí-lo.
1. Exibição de renderizações
1.1 transferência de parâmetros front-end analógico carteiro
Os seguintes valores de campo são passados para representar as colunas que precisam ser exportadas
1.2 Renderizações Excel exportadas
Vamos falar brevemente sobre a ideia e o processo do código:
1. Os campos que precisam ser exportados na transferência de parâmetros front-end e os cabeçalhos do Excel correspondentes aos campos
2. Os campos na primeira etapa do loop, desenhe as células de cada linha de acordo com o conjunto de dados encontrado
3. A chave Etapa 1: Encontre o relacionamento correspondente entre a transmissão de front-end e a participação em nosso conjunto de dados (a lista de entidades de dados encontradas no mysql) e desenhe cada célula de acordo com isso etapa.
Neste artigo, o reflexo da classe de entidade é usado para obter o relacionamento correspondente. Para obter detalhes, consulte o código em "ExportExcel.getValues(Object rowData, String[] exportFieldArr)", o código principal!
2. Exibição de código
2.1. Classe de entidade
2.1.1 dto para receber front-end
/**
* <p>@Description: 用于接收前端传参的dto</p >
* <p>@param </p >
*/
@Data
@JsonIgnoreProperties(ignoreUnknown = true)
public class DynamicExportRequest {
//@ApiModelProperty("前端选择的需要导出的字段")
private GoodsExportBean goodsExportBean;
// 分页参数
private int pageIndex;
private int pageSize;
}
2.1.2 classe de entidade mysql
package com.lzq.learn.test.动态选择列导出excel;
import com.lzq.learn.anno.DynamicExport;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.math.BigDecimal;
import java.time.LocalDateTime;
/**
* <p>@Description: 实体类</p >
* <p>@date 18:58 18:58</p >
* @author 吴巴格
*/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Goods {
private Integer id;
private String name;
private BigDecimal price;
private String type;
private BigDecimal quantity;
private LocalDateTime createTime;
}
2.1.3 dto usado para receber campos front-end que precisam ser exportados
package com.lzq.learn.test.动态选择列导出excel.byExportBean;
import com.lzq.learn.anno.DynamicExport;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
* <p>@Description: 用于接收前端哪些需要导出字段的dto</p >
* <p>@date 9:28 9:28</p >
*/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class GoodsExportBean {
@DynamicExport(sort = 1, name = "id")
private String id;
@DynamicExport(sort = 2, name = "姓名")
private String name;
@DynamicExport(sort = 3, name = "价格")
private String price;
@DynamicExport(sort = 4, name = "类型")
private String type;
@DynamicExport(sort = 5, name = "库存")
private String quantity;
@DynamicExport(sort = 6, name = "创建时间")
private String createTime;
}
2.1.4 Entidades de campo opcionais para o front end
package com.lzq.learn.test.动态选择列导出excel;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
* <p>@Description: 用于返回给前端的可选择导出列 </p >
* <p>@date 14:23 14:23</p >
*/
@Data
@AllArgsConstructor
@NoArgsConstructor
public class DynamicField {
//("字段英文名")
private String englishFiledName;
//("excel显示表头中文名")
private String chineseTitleName;
public static DynamicField build(String englishFiledName, String chineseTitleName) {
DynamicField dynamicField = new DynamicField();
dynamicField.setEnglishFiledName(englishFiledName);
dynamicField.setChineseTitleName(chineseTitleName);
return dynamicField;
}
}
2.2 Classes de ferramentas e anotações
2.2.1 Anotações personalizadas
package com.lzq.learn.anno;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* <p>@Description: 动态导出字段, 将可选字段加上该注解</p >
* <p>@date 10:26 10:26</p >
*/
@Target({
TYPE, FIELD, METHOD})
@Retention(RUNTIME)
public @interface DynamicExport {
int sort() default 0;
String name() default "";
}
2.2.2 Classe de ferramenta de coluna de campo dinâmico
package com.lzq.learn.test.动态选择列导出excel;
import com.lzq.learn.anno.DynamicExport;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
/**
* <p>@Description: 可选择动态字段列工具类</p >
* <p>@date 14:26 14:26</p >
*/
public class DynamicFieldUtil {
/**
* <p>@Description: 带有 @DynamicExport 注解的实体类，利用反射返回可选择动态列</p >
* <p>@param [object]</p >
* <p>@return java.util.List<com.hjza.environment.response.export.DynamicField></p >
* <p>@throws </p >
*/
public static <T> List<DynamicField> exportPageListDynamicFieldList(Class<T> objectClass){
Field[] declaredFields = objectClass.getDeclaredFields();
List<DynamicField> dynamicFieldList = new ArrayList<>();
for (Field declaredField : declaredFields) {
declaredField.setAccessible(true);
DynamicExport dynamicExportAnnotation = declaredField.getAnnotation(DynamicExport.class);
String chineseTitle = dynamicExportAnnotation.name();
dynamicFieldList.add(DynamicField.build(declaredField.getName(), chineseTitle));
}
return dynamicFieldList;
}
}
2.2.3 Principais ferramentas de POI
package com.lzq.learn.test.动态选择列导出excel.byExportBean;
import cn.hutool.core.util.StrUtil;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
/**
* <p>@Description: 将 Apache POI 的一些常用api进行封装</p >
*/
public class ExportExcel {
/**
* <p>@Description: 根据 所选动态列，以及数据集进行导出excel</p >
* <p>@param [exportBeanFrom, dataList, fileName]</p >
* <p>@return void</p >
* <p>@throws </p >
*/
public static <T> void exportByTitleAndData(Object exportBeanFrom, List<T> dataList, String fileName) {
// 处理参数: 需要导出的英文字段名 exportFieldArr, 中文表头 title
Map<String, Object> beanExportFieldMap = ExportExcelSortUtil.filterAndSort(exportBeanFrom);
Map<String, String[]> fieldAndTitleMap = ExportExcelSortUtil.getExportFieldAndExportTitle(beanExportFieldMap);
String[] title = ExportExcelSortUtil.getExportTitleArr(fieldAndTitleMap);
String[] exportFieldArr = ExportExcelSortUtil.getExportFieldArr(fieldAndTitleMap);
// 根据参数 生成工作簿，并写入文件流
if (title.length > 0 && exportFieldArr.length > 0) {
Workbook workbook = ExportExcel.getWorkbook(dataList, exportFieldArr, title);
ExportExcel.writeToResponse(workbook, fileName);
}
}
/**
* <p>@Description: 将文件流写会回 response 中</p >
* <p>@param [workbook, fileName]</p >
* <p>@return void</p >
* <p>@throws </p >
*/
public static void writeToResponse(Workbook workbook, String fileName) {
ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpServletResponse response = attributes.getResponse();
response.setContentType("application/vnd.ms-excel;charset=UTF-8");
response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
OutputStream outputStream = null;
try {
outputStream = response.getOutputStream();
workbook.write(outputStream);
outputStream.flush();
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException(e.getMessage());
}
}
/**
* <p>@Description: 根据 数据集、导出列、表头汉字 创建工作簿</p >
* <p>@param [dataSet 数据集, exportFieldArr 需要导出的字段列, titles 导出列对应的中文表头]</p >
* <p>@return org.apache.poi.xssf.usermodel.XSSFWorkbook</p >
* <p>@date 15:19 15:19</p >
*/
public static <T> XSSFWorkbook getWorkbook(Collection<T> dataSet, String[] exportFieldArr, String[] titles) {
// 校验变量和预期输出excel列数是否相同
if (exportFieldArr.length != titles.length) {
return null;
}
// 存储每一行的数据
List<String[]> list = new ArrayList<>();
for (Object obj : dataSet) {
// 获取到每一行的属性值数组
list.add(getValues(obj, exportFieldArr));
}
return getWorkbook(titles, list);
}
public static XSSFWorkbook getWorkbook(String[] titles, List<String[]> list) {
// 定义表头
String[] title = titles;
// 创建excel工作簿
XSSFWorkbook workbook = new XSSFWorkbook();
// 创建工作表sheet
XSSFSheet sheet = workbook.createSheet();
// 创建第一行
XSSFRow row = sheet.createRow(0);
XSSFCell cell = null;
// 插入第一行数据的表头
row.setHeight((short) (24 * 20));
CellStyle headerCommonStyle = getHeaderCommonStyle(workbook);
for (int i = 0; i < title.length; i++) {
cell = row.createCell(i);
cell.setCellValue(title[i]);
cell.setCellStyle(headerCommonStyle);
}
// 数据行渲染
CellStyle bodyStyle = getBodyStyle(workbook);
int idx = 1;
for (String[] strings : list) {
XSSFRow nrow = sheet.createRow(idx++);
XSSFCell ncell = null;
for (int i = 0; i < strings.length; i++) {
ncell = nrow.createCell(i);
ncell.setCellValue(strings[i]);
ncell.setCellStyle(bodyStyle);
}
}
// 设置固定列宽
setColumnWidth(titles, sheet);
return workbook;
}
// 设置固定列宽
public static void setColumnWidth(String[] titles, Sheet sheet) {
for (int i = 0; i < titles.length; i++) {
sheet.setColumnWidth(i, 20 * 256);
}
}
private static CellStyle getHeaderCommonStyle(Workbook workbook) {
CellStyle header = workbook.createCellStyle();
Font font = workbook.createFont();
font.setBold(Boolean.TRUE);
font.setFontHeightInPoints((short) 14);
font.setFontName("宋体");
header.setFont(font);
header.setBorderTop(BorderStyle.THIN);
header.setBorderLeft(BorderStyle.THIN);
header.setBorderBottom(BorderStyle.THIN);
header.setBorderRight(BorderStyle.THIN);
header.setAlignment(HorizontalAlignment.CENTER);
header.setVerticalAlignment(VerticalAlignment.CENTER);
header.setFillPattern(FillPatternType.SOLID_FOREGROUND);
// header.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
return header;
}
private static CellStyle getBodyStyle(Workbook workbook) {
CellStyle body = workbook.createCellStyle();
Font font = workbook.createFont();
font.setFontHeightInPoints((short) 12);
font.setFontName("宋体");
body.setFont(font);
body.setWrapText(Boolean.TRUE);
body.setBorderTop(BorderStyle.THIN);
body.setBorderLeft(BorderStyle.THIN);
body.setBorderBottom(BorderStyle.THIN);
body.setBorderRight(BorderStyle.THIN);
body.setAlignment(HorizontalAlignment.LEFT);
body.setVerticalAlignment(VerticalAlignment.CENTER);
body.setFillPattern(FillPatternType.SOLID_FOREGROUND);
body.setFillForegroundColor(IndexedColors.WHITE.getIndex());
return body;
}
/**
* <p>@Description: object就是每一行的数据</p >
* <p>@param [rowData, exportFieldArr]</p >
* <p>@return java.lang.String[]</p >
* <p>@throws </p >
*/
public static String[] getValues(Object rowData, String[] exportFieldArr) {
String[] values = new String[exportFieldArr.length];
try {
for (int i = 0; i < exportFieldArr.length; i++) {
Field field = null;
try {
field = rowData.getClass().getDeclaredField(exportFieldArr[i]);
} catch (Exception e) {
field = rowData.getClass().getField(exportFieldArr[i]);
}
// 设置访问权限为true
field.setAccessible(true);
values[i] = setCellValue(field, rowData);
}
} catch (Exception e) {
e.printStackTrace();
}
return values;
}
public static String setCellValue(Field field, Object data) {
Class<?> fieldType = field.getType();
String result = "";
try {
Method method = data.getClass().getMethod(getMethodNameByCamel("get", field.getName()));
Object fieldValue = method.invoke(data);
if (fieldType == String.class) {
result = (method.invoke(data) == null ? null : method.invoke(data).toString());
} else if (fieldType == Short.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == Integer.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == Long.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == Float.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == Double.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == BigDecimal.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == Boolean.class) {
result = returnStringFromNumber(fieldValue);
} else if (fieldType == LocalDate.class) {
String pattern = "yyyy-MM-dd";
LocalDate date = method.invoke(data) == null ? null : (LocalDate) method.invoke(data);
if (date != null) {
result = (date.format(DateTimeFormatter.ofPattern(pattern)));
}
} else if (fieldType == LocalDateTime.class) {
String pattern = "yyyy-MM-dd HH:mm:ss";
LocalDateTime date = method.invoke(data) == null ? null : (LocalDateTime) method.invoke(data);
if (date != null) {
result = (date.format(DateTimeFormatter.ofPattern(pattern)));
}
} else {
result = (method.invoke(data) == null ? null : method.invoke(data).toString());
}
return result;
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
return result;
}
// 将数字转换为 保留两位小数的字符串
public static String returnStringFromNumber(Object data) {
if (data == null || StrUtil.isBlank(data.toString())) {
return "";
}
Double aDouble = Double.valueOf(data.toString());
DecimalFormat decimalFormat = new DecimalFormat("0.00");
String result = decimalFormat.format(aDouble);
return result;
}
/**
* <p>@Description: 拼接前缀以及方法名，驼峰形式</p >
* <p>@param [prefix, fieldName]</p >
* <p>@return java.lang.String</p >
* <p>@throws </p >
*/
private static String getMethodNameByCamel(String prefix, String fieldName) {
StringBuilder builder = new StringBuilder()
.append(prefix)
.append(fieldName.substring(0, 1).toUpperCase())
.append(fieldName.substring(1));
return builder.toString();
}
}
2.3 Camada de chamada comercial
2.3.1 controlador
import com.lzq.learn.domain.CommonResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
/**
* @author 吴巴哥
*/
@RestController
@RequestMapping("/dynamic")
public class TestDynamicExcelController {
@Autowired
private DynamicExportService dynamicExportService;
// 方式一：通过注解的形式，动态导出excel
@PostMapping("/exportByFields")
public void exportByFields(@RequestBody DynamicExportRequest dynamicExportRequest) {
dynamicExportService.exportByFields(dynamicExportRequest , "1.xlsx");
}
//("返回给前端的导出Excel的动态列")
@GetMapping("/getDynamicFields")
public CommonResult getDynamicFields() {
List<DynamicField> dynamicFieldList = dynamicExportService.getDynamicFields();
return CommonResult.success(dynamicFieldList, "获取成功");
}
}
2.3.2 código de serviço
import com.lzq.learn.test.动态选择列导出excel.byExportBean.ExportExcel;
import com.lzq.learn.test.动态选择列导出excel.byExportBean.GoodsExportBean;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import java.math.BigDecimal;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;
@Service
@Slf4j
public class DynamicExportService {
// 模拟从 mysql 获取数据
public List getDataList() {
ArrayList<Goods> goodsList = new ArrayList<>();
for (int i = 0; i < 10; i++) {
BigDecimal quantity = BigDecimal.TEN.add(BigDecimal.valueOf(i));
Goods goods = new Goods(i, "商品"+i, BigDecimal.valueOf(i), "类型"+i, quantity, LocalDateTime.now());
goodsList.add(goods);
}
return goodsList;
}
public void exportStaticsByReflect(DynamicExportRequest dynamicExportRequest, String fileName) {
}
public void exportByFields(DynamicExportRequest dynamicExportRequest, String fileName) {
List<Goods> dataList = this.getDataList();
GoodsExportBean goodsExportBean = dynamicExportRequest.getGoodsExportBean();
ExportExcel.exportByTitleAndData(goodsExportBean, dataList, fileName);
}
public List<DynamicField> getDynamicFields() {
List<DynamicField> dynamicFieldList = DynamicFieldUtil.exportPageListDynamicFieldList(GoodsExportBean.class);
return dynamicFieldList;
}
}
3. Exemplo de chamada de interface do carteiro
3.1 Obter colunas de campo de exportação opcionais
Endereço da interface: localhost:8089/dynamic/getDynamicFields
O valor de retorno da interface é o seguinte
{
"code": 200,
"message": "获取成功",
"data": [
{
"englishFiledName": "id",
"chineseTitleName": "id"
},
{
"englishFiledName": "name",
"chineseTitleName": "姓名"
},
{
"englishFiledName": "price",
"chineseTitleName": "价格"
},
{
"englishFiledName": "type",
"chineseTitleName": "类型"
},
{
"englishFiledName": "quantity",
"chineseTitleName": "库存"
},
{
"englishFiledName": "createTime",
"chineseTitleName": "创建时间"
}
]
}
3.2 Exportar Excel após selecionar os campos
Endereço da interface: localhost:8089/dynamic/exportByFields
solicitação de postagem, o formato de passagem de parâmetro é o seguinte
{
"goodsExportBean":{
//"id":"主键",
"name":"商品名称",
"price":"价格",
//"type":"类型",
"quantity":"库存哦"
//"createTime":"上架时间"
}
}
Finalmente, onde o texto não é atencioso, espero que vocês possam fornecer comentários ativamente, aceitarei com humildade e corrigirei a tempo!