easyexcel讀取

pom依賴，easyexcel是必須的，lombok非必須，它可以在實體類上使用@Data注釋，無需生成get、set方法

    <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.0.5</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.8</version>
            <scope>provided</scope>
        </dependency>

　　實體類

public class Province {

    @ExcelProperty(index = 0)
    private Long provinceId;

    @ExcelProperty(index = 1)
    private String provinceName;

    @ExcelProperty(index = 2)
    private Long cityId;

    @ExcelProperty(index = 3)
    private String cityName;

    public Long getCityId() {
        return cityId;
    }

    public void setCityId(Long cityId) {
        this.cityId = cityId;
    }

    public String getCityName() {
        return cityName;
    }

    public void setCityName(String cityName) {
        this.cityName = cityName;
    }

    public Long getProvinceId() {
        return provinceId;
    }

    public void setProvinceId(Long provinceId) {
        this.provinceId = provinceId;
    }

    public String getProvinceName() {
        return provinceName;
    }

    public void setProvinceName(String provinceName) {
        this.provinceName = provinceName;
    }
}

　　excel監聽器(需注意的是，要將dao傳入進去，也就是每一個監聽器只操作一種類型的

/**
 * 使用EasyExcel處理excel文件
 * @Version 1.0.0
 * @Description
 */
public class ProvinceExcelListener extends AnalysisEventListener<Province> {

    private ProvinceMapper provinceMapper;

    /**
     * 批處理閾值
     */
    private static final int BATCH_COUNT = 1000;
    List<Province> list = new ArrayList<Province>(BATCH_COUNT); //存放數據

    public ProvinceExcelListener(ProvinceMapper provinceMapper){
        this.provinceMapper = provinceMapper;
    }

    @Override
    public void invoke(Province province, AnalysisContext context) {
        list.add(province);
        //內存存放超過多少條數據，則先存放到數據庫中；保存完后，清空內存
        if(list.size() >= BATCH_COUNT){
            long beforeTime = System.currentTimeMillis();
            saveData();
            list.clear();//清空內存
            System.out.println("處理1000數據所需的時間："+(System.currentTimeMillis()-beforeTime));
        }
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
　　　　　　saveData();//解析完成后需要調用一次，不大於BATCH_COUNT就沒處理
    }

    /**
     * 保存數據
     */
    private void saveData(){
        for(Province province : list){
            provinceMapper.add(province);
        }
    }
}

　　測試類

@Test
    void contextLoads()throws Exception {

        String fileName = "C:/Users/zwk/Desktop/工作簿1.xlsx";
        long beforeTime = System.currentTimeMillis();
        EasyExcel.read(fileName,Province.class,new ProvinceExcelListener(provinceMapper)).sheet().doRead();
        System.out.println("讀取數據所花的時間："+(System.currentTimeMillis()-beforeTime)+"毫秒");
    }

　　注：空的也能讀取，不用特殊處理