java使用ExcelWriter保存表格到本地

以下是使用ExcelWriter保存表格到本地的Java示例代码：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.alibaba.excel.write.metadata.WriteTable;
import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import com.alibaba.excel.write.style.HorizontalCellStyleStrategy;

public class ExcelWriterDemo {

    public static void main(String[] args) throws IOException {
        // 创建ExcelWriter对象
        FileOutputStream outputStream = new FileOutputStream(new File("test.xlsx"));
        ExcelWriter excelWriter = EasyExcel.write(outputStream).build();
        
        // 设置表格样式
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        headWriteCellStyle.setWrapped(true);
        WriteCellStyle contentWriteCellStyle = new WriteCellStyle();
        contentWriteCellStyle.setWrapped(true);
        HorizontalCellStyleStrategy styleStrategy = new HorizontalCellStyleStrategy(headWriteCellStyle, contentWriteCellStyle);
        
        // 准备数据
        List<DemoData> data = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            DemoData demoData = new DemoData();
            demoData.setString("字符串" + i);
            demoData.setDate(new Date());
            demoData.setDoubleData(0.56);
            data.add(demoData);
        }
        
        // 写入数据
        WriteSheet writeSheet = EasyExcel.writerSheet("测试Sheet").build();
        WriteTable writeTable = EasyExcel.writerTable(0).head(DemoData.class).registerWriteHandler(styleStrategy).build();
        excelWriter.write(data, writeSheet, writeTable);
        
        // 关闭ExcelWriter对象
        excelWriter.finish();
    }

}

在上面的示例代码中，我们使用EasyExcel库提供的ExcelWriter对象将数据写入到Excel文件中，最后通过调用`finish()`方法关闭ExcelWriter对象即可完成保存操作。同时，我们还可以通过设置`HorizontalCellStyleStrategy`对象来自定义表格的样式。