掌握这些操作Excel的神器,让你代码高出一个逼格(三)

导出的文件预览如下:

掌握这些操作Excel的神器,让你代码高出一个逼格(三)

对应的导入操作,也很简单,源码如下:

public static void main(String[] args) {
    ImportParams params = new ImportParams();
    params.setTitleRows(1);
    params.setHeadRows(1);
    long start = new Date().getTime();
    List<StudentEntity> list = ExcelImportUtil.importExcel(new File("/Users/hello/Documents/easypoi-user1.xls"),
            UserEntity.class, params);
    System.out.println(new Date().getTime() - start);
    System.out.println(JSONArray.toJSONString(list));
}

运行程序,输出结果如下:

[{"age":20,"name":"张三0","time":1616919493000},{"age":21,"name":"张三1","time":1616919493000},{"age":22,"name":"张三2","time":1616919493000},{"age":23,"name":"张三3","time":1616919493000},{"age":24,"name":"张三4","time":1616919493000},{"age":25,"name":"张三5","time":1616919493000},{"age":26,"name":"张三6","time":1616919493000},{"age":27,"name":"张三7","time":1616919493000},{"age":28,"name":"张三8","time":1616919493000},{"age":29,"name":"张三9","time":1616919493000}]

3.3、自定义数据结构导出导入

easypoi 同样也支持自定义数据结构导出导入excel。

  • 自定义数据导出 excel
public static void main(String[] args) throws Exception {
    //封装表头
    List<ExcelExportEntity> entityList = new ArrayList<ExcelExportEntity>();
    entityList.add(new ExcelExportEntity("姓名", "name"));
    entityList.add(new ExcelExportEntity("年龄", "age"));
    ExcelExportEntity entityTime = new ExcelExportEntity("操作时间", "time");
    entityTime.setFormat("yyyy-MM-dd HH:mm:ss");
    entityTime.setWidth(20.0);
    entityList.add(entityTime);
    //封装数据体
    List<Map<String, Object>> dataList = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        Map<String, Object> userEntityMap = new HashMap<>();
        userEntityMap.put("name", "张三" + i);
        userEntityMap.put("age", 20 + i);
        userEntityMap.put("time", new Date(System.currentTimeMillis() + i));
        dataList.add(userEntityMap);
    }
    //生成excel文档
    Workbook workbook = ExcelExportUtil.exportExcel(new ExportParams("学生","用户信息"), entityList, dataList);
    FileOutputStream fos = new FileOutputStream("/Users/panzhi/Documents/easypoi-user2.xls");
    workbook.write(fos);
    fos.close();
}
  • 导入 excel
public static void main(String[] args) {
    ImportParams params = new ImportParams();
    params.setTitleRows(1);
    params.setHeadRows(1);
    long start = new Date().getTime();
    List<Map<String, Object>> list = ExcelImportUtil.importExcel(new File("/Users/panzhi/Documents/easypoi-user2.xls"),
            Map.class, params);
    System.out.println(new Date().getTime() - start);
    System.out.println(JSONArray.toJSONString(list));
}

更多的 api 操作可以访问 Easypoi - 接口文档

四、easyexcel

easyexcel 是阿里巴巴开源的一款 excel 解析工具,底层逻辑也是基于 apache poi 进行二次开发的。不同的是,再读写数据的时候,采用 sax 模式一行一行解析,在并发量很大的情况下,依然能稳定运行!

下面,我们就一起来了解一下这款新起之秀!

4.1、首先添加依赖包

<dependencies>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>easyexcel</artifactId>
        <version>2.2.6</version>
    </dependency>
 <!--常用工具库-->
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>29.0-jre</version>
    </dependency>
</dependencies>

4.2、采用注解导出导入

easyexcel 同样也支持采用注解方式进行导出、导入!

首先,我们创建一个实体类UserEntity,其中@ExcelProperty注解表示导出文件的头部信息。

public class UserEntity {
    @ExcelProperty(value = "姓名")
    private String name;
    @ExcelProperty(value = "年龄")
    private int age;
    @DateTimeFormat("yyyy-MM-dd HH:mm:ss")
    @ExcelProperty(value = "操作时间")
    private Date time;
    
    //set、get省略
}

接着,我们来编写导出服务!

public static void main(String[] args) {
    List<UserEntity> dataList = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        UserEntity userEntity = new UserEntity();
        userEntity.setName("张三" + i);
        userEntity.setAge(20 + i);
        userEntity.setTime(new Date(System.currentTimeMillis() + i));
        dataList.add(userEntity);
    }
    EasyExcel.write("/Users/hello/Documents/easyexcel-user1.xls", UserEntity.class).sheet("用户信息").doWrite(dataList);
}

导出的文件预览如下:

掌握这些操作Excel的神器,让你代码高出一个逼格(三)

对应的导入操作,也很简单,源码如下:

public static void main(String[] args) {
    String filePath = "/Users/hello/Documents/easyexcel-user1.xls";
    List<DemoData> list = EasyExcel.read(filePath).head(UserEntity.class).sheet().doReadSync();
    System.out.println(JSONArray.toJSONString(list));
}

运行程序,输出结果如下:

[{"age":20,"name":"张三0","time":1616920360000},{"age":21,"name":"张三1","time":1616920360000},{"age":22,"name":"张三2","time":1616920360000},{"age":23,"name":"张三3","time":1616920360000},{"age":24,"name":"张三4","time":1616920360000},{"age":25,"name":"张三5","time":1616920360000},{"age":26,"name":"张三6","time":1616920360000},{"age":27,"name":"张三7","time":1616920360000},{"age":28,"name":"张三8","time":1616920360000},{"age":29,"name":"张三9","time":1616920360000}]

4.3、自定义数据结构导出导入

easyexcel 同样也支持自定义数据结构导出导入excel。

  • 自定义数据导出 excel
public static void main(String[] args) {
    //表头
    List<List<String>> headList = new ArrayList<>();
    headList.add(Lists.newArrayList("姓名"));
    headList.add(Lists.newArrayList("年龄"));
    headList.add(Lists.newArrayList("操作时间"));
    //数据体
    List<List<Object>> dataList = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        List<Object> data = new ArrayList<>();
        data.add("张三" + i);
        data.add(20 + i);
        data.add(new Date(System.currentTimeMillis() + i));
        dataList.add(data);
    }
    EasyExcel.write("/Users/hello/Documents/easyexcel-user2.xls").head(headList).sheet("用户信息").doWrite(dataList);
}
  • 导入 excel
public static void main(String[] args) {
    String filePath = "/Users/panzhi/Documents/easyexcel-user2.xls";
    UserDataListener userDataListener = new UserDataListener();
    EasyExcel.read(filePath, userDataListener).sheet().doRead();
    System.out.println("表头:" + JSONArray.toJSONString(userDataListener.getHeadList()));
    System.out.println("数据体:" + JSONArray.toJSONString(userDataListener.getDataList()));
}

运行程序,输出结果如下:

表头:[{0:"姓名",1:"年龄",2:"操作时间"}]
数据体:[{0:"张三0",1:"20",2:"2021-03-28 16:31:39"},{0:"张三1",1:"21",2:"2021-03-28 16:31:39"},{0:"张三2",1:"22",2:"2021-03-28 16:31:39"},{0:"张三3",1:"23",2:"2021-03-28 16:31:39"},{0:"张三4",1:"24",2:"2021-03-28 16:31:39"},{0:"张三5",1:"25",2:"2021-03-28 16:31:39"},{0:"张三6",1:"26",2:"2021-03-28 16:31:39"},{0:"张三7",1:"27",2:"2021-03-28 16:31:39"},{0:"张三8",1:"28",2:"2021-03-28 16:31:39"},{0:"张三9",1:"29",2:"2021-03-28 16:31:39"}]

更多的 api 操作可以访问 easyexcel - 接口文档

五、小结

总体来说,easypoi和easyexcel都是基于apache poi进行二次开发的。

不同点在于:

1、easypoi 在读写数据的时候,优先是先将数据写入内存,优点是读写性能非常高,但是当数据量很大的时候,会出现oom,当然它也提供了 sax 模式的读写方式,需要调用特定的方法实现。

2、easyexcel 基于sax模式进行读写数据,不会出现oom情况,程序有过高并发场景的验证,因此程序运行比较稳定,相对于 easypoi 来说,读写性能稍慢!

easypoi 与 easyexcel 还有一点区别在于,easypoi 对定制化的导出支持非常的丰富,如果当前的项目需求,并发量不大、数据量也不大,但是需要导出 excel 的文件样式千差万别,那么我推荐你用 easypoi;反之,使用 easyexcel !

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