制作网站建设规划书,互联网营销具体做什么,百度新网站收录,近期莱芜命案文章目录 前言正文一、POM依赖二、核心Java文件2.1 自定义表头注解 ExcelColumnTitle2.2 自定义标题头的映射接口2.3 自定义有序map存储表内数据2.4 表头工厂2.5 表flag和表头映射枚举2.6 测试用的实体2.6.1 NameAndFactoryDemo2.6.2 StudentDemo 2.7 启动类2.8 测试控制器 三、… 文章目录 前言正文一、POM依赖二、核心Java文件2.1 自定义表头注解 ExcelColumnTitle2.2 自定义标题头的映射接口2.3 自定义有序map存储表内数据2.4 表头工厂2.5 表flag和表头映射枚举2.6 测试用的实体2.6.1 NameAndFactoryDemo2.6.2 StudentDemo 2.7 启动类2.8 测试控制器 三、测试测试1测试2测试3测试4 前言
日前看到一个比较奇怪的导出功能。
需要根据不同的页面以及指定不同的字段列表任意顺序然后导出对应的表格。 先假设一个场景 假如你的系统有多个列表展示页每页中可以依据筛选条件调整展示的列的个数顺序等。然后要求导出的时侯导出一摸一样的格式。也就是“所见即所得”的表格。 那么基于以上场景我们就来考虑下如何实现 本文就是对以上场景功能的一个实现。目前仅支持单sheet不支持数据聚合等。
正文
本文项目环境 java 8springboot2.2.0, easyexcel
一、POM依赖
dependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-web/artifactIdversion2.2.0.RELEASE/version/dependencydependencygroupIdorg.projectlombok/groupIdartifactIdlombok/artifactIdversion1.18.2/version/dependencydependencygroupIdcom.alibaba/groupIdartifactIdeasyexcel/artifactIdversion2.2.11/versionexclusionsexclusiongroupIdorg.slf4j/groupIdartifactIdslf4j-api/artifactId/exclusion/exclusions/dependency/dependencies
二、核心Java文件
此处粘贴全部的java文件
2.1 自定义表头注解 ExcelColumnTitle
package headbean;import java.lang.annotation.*;/*** 列名标题注解标注列的标题** author feng*/
Documented
Target({ElementType.FIELD})
Retention(RetentionPolicy.RUNTIME)
public interface ExcelColumnTitle {String value();
}2.2 自定义标题头的映射接口
此接口仅仅是用于规范实体以及用于辅助实现导出功能。
package headbean;/*** excel头部映射接口用于规范导出的实体类** author feng*/
public interface ExcelHeadMapInterface {
}2.3 自定义有序map存储表内数据
这个是表格导出时字段数量顺序的关键。
package headbean;import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;/*** 表格数据专用的map带顺序而且初始化的时候依据指定的表头变量字段名确定导出数据的顺序** author feng*/
public class ExcelDataLinkedHashMapV extends LinkedHashMapString, V {private static final long serialVersionUID -8554095999151235982L;/*** 头部字段名缓存*/private final SetString headColumnNamesCache;/*** ExcelDataLinkedHashMap构造器** param headColumnNames 表头字段变量名例如[name,studentNo,age,className]*/public ExcelDataLinkedHashMap(ListString headColumnNames) {// 字段名去重headColumnNames headColumnNames.stream().distinct().collect(Collectors.toList());// 构建字段名缓存this.headColumnNamesCache new HashSet(headColumnNames);// 指定列数据排列顺序for (String headColumnName : headColumnNames) {this.put(headColumnName, null);}}Overridepublic V put(String key, V value) {// 只保存字段名缓存中的key以及valueif (headColumnNamesCache.contains(key)) {return super.put(key, value);}return null;}
}
2.4 表头工厂
负责实现初始化表头字段名以及后期使用时从中获取表头信息。 核心功能是解析自定义的表头注解。
package factory;import enums.ExcelHeadBeanFlagEnum;
import headbean.ExcelColumnTitle;
import headbean.ExcelHeadMapInterface;import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;public class ExcelHeadMapFactory {/*** 全局表头名映射ExcelHeadMapInterface实现类型为key它内部变量的变量名和中文名映射为value*/private static final MapClass? extends ExcelHeadMapInterface, MapString, String HEAD_NAME_MAP new HashMap();public static void addHeadClass(Class? extends ExcelHeadMapInterface headClass) {HEAD_NAME_MAP.put(headClass, mapToPrepareHead(headClass));}public static MapString, String getHeadMap(Class? extends ExcelHeadMapInterface headClass) {return HEAD_NAME_MAP.get(headClass);}public static MapString, String getHeadMapByFlag(String flag) {return getHeadMap(ExcelHeadBeanFlagEnum.getHeadClass(flag));}private static MapString, String mapToPrepareHead(Class? excelHeadClass) {MapString, String namedMap new HashMap();Field[] declaredFields excelHeadClass.getDeclaredFields();for (Field declaredField : declaredFields) {boolean annotationPresent declaredField.isAnnotationPresent(ExcelColumnTitle.class);if(annotationPresent) {ExcelColumnTitle excelProperty declaredField.getAnnotation(ExcelColumnTitle.class);String chineseFieldName excelProperty.value();// 保存字段名和中文变量名namedMap.put(declaredField.getName(), chineseFieldName);}}return namedMap;}
}2.5 表flag和表头映射枚举
这个枚举如果你的系统这类功能很多。可以设计为数据库的方式做映射。然后以查字典表的方式来处理。当然使用枚举大概率是够用了。
package enums;import headbean.ExcelHeadMapInterface;
import headbean.NameAndFactoryDemo;
import headbean.StudentDemo;
import lombok.AllArgsConstructor;
import lombok.Getter;import java.util.Arrays;/*** 表头flag枚举映射flag与对应的实体类型主要是可以根据flag找到对应实体类型。** author feng*/
Getter
AllArgsConstructor
public enum ExcelHeadBeanFlagEnum {NAME_AND_FACTORY_DEMO(NameAndFactoryDemo, NameAndFactoryDemo.class),STUDENT_DEMO(StudentDemo, StudentDemo.class);private final String flag;private final Class? extends ExcelHeadMapInterface headClass;public static Class? extends ExcelHeadMapInterface getHeadClass(String flag) {return Arrays.stream(values()).filter(bean - bean.getFlag().equals(flag)).findFirst().orElseThrow(RuntimeException::new).getHeadClass();}
}
2.6 测试用的实体
2.6.1 NameAndFactoryDemo
package headbean;import lombok.Data;Data
public class NameAndFactoryDemo implements ExcelHeadMapInterface {ExcelColumnTitle(名字)private String name;ExcelColumnTitle(工厂)private String factory;
}
2.6.2 StudentDemo
package headbean;import lombok.Data;Data
public class StudentDemo implements ExcelHeadMapInterface {ExcelColumnTitle(姓名)private String name;ExcelColumnTitle(年龄)private Integer age;ExcelColumnTitle(学号)private String studentNo;ExcelColumnTitle(班级)private String className;
}2.7 启动类
主要是项目启动后注册表头数据到内存。
package org.feng;import factory.ExcelHeadMapFactory;
import headbean.ExcelHeadMapInterface;
import headbean.NameAndFactoryDemo;
import headbean.StudentDemo;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;import java.util.ArrayList;
import java.util.List;SpringBootApplication
public class ExcelDemoApplication implements CommandLineRunner {public static void main(String[] args) {SpringApplication.run(ExcelDemoApplication.class, args);}Overridepublic void run(String... args) throws Exception {ListClass? extends ExcelHeadMapInterface needRegisterExcelHeadClassList new ArrayList();needRegisterExcelHeadClassList.add(NameAndFactoryDemo.class);needRegisterExcelHeadClassList.add(StudentDemo.class);needRegisterExcelHeadClassList.forEach(ExcelHeadMapFactory::addHeadClass);}
}
2.8 测试控制器
package org.feng;import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.write.metadata.WriteSheet;
import enums.ExcelHeadBeanFlagEnum;
import factory.ExcelHeadMapFactory;
import headbean.ExcelDataLinkedHashMap;
import headbean.ExcelHeadMapInterface;
import headbean.NameAndFactoryDemo;
import headbean.StudentDemo;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;import javax.annotation.PostConstruct;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.*;
import java.util.function.BiFunction;Controller
RequestMapping(/excel)
public class ExcelDemoController {GetMapping(/exportDy)public String exportDy(RequestParam(flag)String flag,RequestParam(table)ListString table, HttpServletResponse response) throws IOException {String fileName System.currentTimeMillis() .xlsx;Class? extends ExcelHeadMapInterface headClass ExcelHeadBeanFlagEnum.getHeadClass(flag);MapString, String namedPrepareHeadMap ExcelHeadMapFactory.getHeadMap(headClass);MapString, String head new LinkedHashMap();for (String fieldName : table) {head.put(namedPrepareHeadMap.get(fieldName), fieldName);}ListMapString, String excelDataList new ArrayList();excelDataList.add(head);// 制造假数据for (BiFunctionClass? extends ExcelHeadMapInterface, ListMapString, String, Boolean biFunction : bizList) {Boolean applied biFunction.apply(headClass, excelDataList);if(applied) {break;}}byte[] bytes easyOut(excelDataList);response.setHeader(Content-disposition, attachment;filename fileName);response.setContentType(application/x-msdownload);response.setCharacterEncoding(utf-8);response.getOutputStream().write(bytes);response.getOutputStream().flush();return success;}static final ListBiFunctionClass? extends ExcelHeadMapInterface, ListMapString, String, Boolean bizList new ArrayList();PostConstructprivate void init() {bizList.add(this::genStudentDemoData);bizList.add(this::genNameAndFactoryDemoData);}private boolean genStudentDemoData(Class? extends ExcelHeadMapInterface headClass, ListMapString, String excelDataList) {if(headClass StudentDemo.class) {MapString, String headMap excelDataList.get(0);for (int i 0; i 5; i) {CollectionString fieldNames headMap.values();MapString, String data new ExcelDataLinkedHashMap(new ArrayList(fieldNames));excelDataList.add(data);data.put(name, 张三(i1));data.put(age, 年龄(i1));data.put(studentNo, 学号(i1));data.put(className, 班级(i1));}return true;}return false;}private boolean genNameAndFactoryDemoData(Class? extends ExcelHeadMapInterface headClass, ListMapString, String excelDataList) {if(headClass NameAndFactoryDemo.class) {MapString, String headMap excelDataList.get(0);for (int i 0; i 5; i) {CollectionString fieldNames headMap.values();MapString, String data new ExcelDataLinkedHashMap(new ArrayList(fieldNames));excelDataList.add(data);data.put(name, 张三(i1));data.put(factory, 工厂(i1));}return true;}return false;}/*** 导出数据单sheet* param exportData key 是sheet名称value是每个sheet里面的数据支持自定义表头*/public static byte[] easyOut(ListMapString, String exportData) {return easyOut(Collections.singletonMap(Sheet, exportData));}/*** 导出数据多sheet* param exportData key 是sheet名称value是每个sheet里面的数据可以自定义*/public static byte[] easyOut(MapString, ListMapString, String exportData) {// 导出数据ByteArrayOutputStream out new ByteArrayOutputStream();com.alibaba.excel.ExcelWriter excelWriter EasyExcel.write(out).build();int i0;for (Map.EntryString, ListMapString, String entry: exportData.entrySet()) {WriteSheet writeSheet EasyExcel.writerSheet(i, entry.getKey()).head(head(entry.getValue().get(0))).build();i;excelWriter.write(data(entry.getValue(), true), writeSheet);}excelWriter.finish();return out.toByteArray();}private static ListListString head(MapString, String cellData) {ListListString head new ArrayList();for (String key: cellData.keySet()) {head.add(Collections.singletonList(key));}return head;}private static ListListString data(ListMapString, String sheetData, boolean skipHead) {ListListString data new ArrayList();for (int i 0; i sheetData.size(); i) {if(i 0 skipHead) {continue;}data.add(new ArrayList(sheetData.get(i).values()));}return data;}
}
三、测试
测试1
http://localhost:8080/excel/exportDy?flagStudentDemotablename,studentNo,age,className
获得的表格内容为
测试2
http://localhost:8080/excel/exportDy?flagStudentDemotablename,studentNo,age
获得的表格内容为
测试3
http://localhost:8080/excel/exportDy?flagNameAndFactoryDemotablefactory,name 获得的表格内容为
测试4
http://localhost:8080/excel/exportDy?flagStudentDemotableclassName,name,studentNo 获得的表格内容为
