通过easyexcel导出数据到excel表格

这篇文章简单介绍一下怎么通过easyexcel做数据的导出，使用之前easyui构建的歌曲列表crud应用，添加一个导出按钮，点击的时候直接连接后端接口地址，在后端的接口完成数据的导出功能。

前端页面完整代码

let editingId;
let requestUrl;
let base = "http://localhost:8083";
let pageList = [20, 50, 100, 500, 1000];

// 定义一个json对象保存歌曲数据
let data = {};

function addHandler() {
	requestUrl = "/song/insert";
	
	$.post(base + requestUrl, {
		name: "*****",
		singer: "*****",
		note: "*****"
	}, function () {
		$("#song_list").datagrid("reload");
	}, "json");
}

function editHandler() {
	let datagrid = $("#song_list");
	let row = datagrid.datagrid("getSelected");

	if (editingId != null && editingId != "") {
		datagrid.datagrid("selectRow", editingId);
	} else {
		if (row) {
			// 获取行索引，这个索引从0开始
			let rowIndex = datagrid.datagrid("getRowIndex", row);
			
			editingId = rowIndex;
			requestUrl = "/song/updateById";

			datagrid.datagrid("beginEdit", rowIndex);
		}
	}
}

function saveHandler() {
	if (editingId) {
		// 只有结束编辑才能获取到最新的值
		$("#song_list").datagrid("endEdit", editingId);
	
		$.post(base + requestUrl, data, function (res) {
			$.messager.show({
				title: '系统消息',
				timeout: 5000,
				showType: 'slide',
				msg: res.message,
			});
			
			editingId = "";
		}, "json");
	}
}

function cancelHandler() {
	// editingId != null条件防止刷新页面带来的问题
	if (editingId != null && editingId !== "") {
		$("#song_list").datagrid("cancelEdit", editingId);
	
		editingId = "";
	}
}

function exportHandler() {
	location.href = base + "/song/export";
}

function deleteHandler() {
	let rowData = $("#song_list").datagrid("getSelected");
	
	if (rowData) {
		$.messager.confirm("提示", "删除后数据无法恢复，是否确认删除？", function(bool) {
			if (bool) {
				$.get(base + "/song/deleteById/" + rowData.id, {}, function(res) {
					$.messager.show({
						title: '系统消息',
						timeout: 5000,
						showType: 'slide',
						msg: res.message,
					});
				
					$("#song_list").datagrid("reload");
				}, "json");
			}
		});
	} else {
		$.messager.alert("请选择要删除的数据！", "warning");
	}
}

$(document).ready(function() {
	let datagrid = $("#song_list").datagrid({
		url: base + "/song/selectByPage",
		title: "歌曲列表",
		height: 810,
		striped: true,
		fitColumns: true,
		singleSelect: true,
		pagination: true,
		remoteFilter: true,
		clientPaging: false,
		pageSize: pageList[0],
		pageList: pageList,
		loadFilter: function(res) {
			if (res.code == 200) {
				return res.data;
			} else {
				return null;
			}
		},
		onAfterEdit: function (rowIndex, rowData, changes) { // 结束行内编辑事件
			data = {
				id: rowData.id,
				name: changes.name ? changes.name : rowData.name,
				note: changes.note ? changes.note : rowData.note,
				singer: changes.singer ? changes.singer : rowData.singer
			};
		},
		toolbar: [{
			iconCls: 'icon-add',
			text: '添加',
			handler: function() {
				addHandler();
			}
		}, '-', {
			iconCls: 'icon-edit',
			text: '修改',
			handler: function() {
				editHandler();
			},
		}, "-", {
			iconCls: "icon-save",
			text: "保存",
			handler: function() {
				saveHandler();
			}
		}, "-", {
			iconCls: "icon-cancel",
			text: "取消",
			handler: function() {
				cancelHandler();
			}
		}, '-', {
			iconCls: 'icon-ok',
			text: '导出',
			handler: function() {
				exportHandler();
			}
		}, '-', {
			iconCls: 'icon-delete',
			text: '删除',
			handler: function() {
				deleteHandler();
			},
		}],
		columns: [[
			{field: 'id', title: 'id', width: 200},
			{field: 'name', title: 'name', width: 200, editor: "textbox"},
			{field: 'singer', title: 'singer', width: 200, editor: "textbox"},
			{field: 'note', title: 'note', width: 200, editor: "textbox"},
			{field: 'lastUpdateTime', title: 'lastUpdateTime', width: 200},
		]]
	});
	
	datagrid.datagrid('enableFilter', [{
		field: 'name',
		type: 'textbox',
		op: ['equal', 'contains']
	}, {
		field: 'singer',
		type: 'textbox',
		op: ['equal', 'contains'],
	}, {
		field: 'note',
		type: 'textbox',
		op: ['equal', 'contains']
	}]);

});

添加依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>3.3.2</version>
</dependency>

修改实体类，添加列注解

package com.example.springboot.entity;

import com.alibaba.excel.annotation.ExcelIgnore;
import com.alibaba.excel.annotation.ExcelProperty;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.Data;

import java.io.Serializable;
import java.time.LocalDateTime;

/**
 * 歌曲
 * @author heyunlin
 * @version 1.0
 */
@Data
@TableName("song")
public class Song implements Serializable {
    private static final long serialVersionUID = 18L;

    @ExcelIgnore
    @TableId(type = IdType.INPUT)
    private String id;

    /**
     * 歌曲名
     */
    @ExcelProperty("歌曲名")
    private String name;

    /**
     * 歌手
     */
    @ExcelProperty("歌手")
    private String singer;

    /**
     * 描述信息
     */
    @ExcelProperty("描述信息")
    private String note;

    /**
     * 最后一次修改时间
     */
    @TableField("last_update_time")
    @ExcelProperty("最后一次修改时间")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private LocalDateTime lastUpdateTime;
}

参考官网的案例代码，完成后端controller接口具体代码实现

package com.example.springboot.service.impl;

import com.alibaba.excel.EasyExcel;
import com.example.springboot.entity.Song;
import com.example.springboot.mapper.SongMapper;
import com.example.springboot.restful.JsonResult;
import com.example.springboot.service.SongService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

/**
 * @author heyunlin
 * @version 1.0
 */
@Service
public class SongServiceImpl implements SongService {

    private final SongMapper songMapper;

    @Autowired
    public SongServiceImpl(SongMapper songMapper) {
        this.songMapper = songMapper;
    }

    // 其他代码...

    @Override
    public void export(HttpServletResponse response) {
        String fileName = "song.xlsx";

        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-disposition", "attachment;filename=" + fileName);
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");

        try {
            List<Song> songs = songMapper.selectList(null);

            EasyExcel.write(response.getOutputStream(), Song.class).sheet("歌曲列表").doWrite(songs);
        } catch (Exception e) {
            e.printStackTrace();

            response.reset();
            response.setContentType("application/json;charset=utf-8");
            JsonResult<Void> jsonResult = JsonResult.success("数据导出异常");

            try {
                response.getWriter().write(jsonResult.toString());
            } catch (IOException ioException) {
                ioException.printStackTrace();
            }
        }
    }

}