1、查询某张表字段信息

select column_name as columnName, -- 字段名
COLUMN_DEFAULT as colDefault,  -- 默认值
column_key as columnKey, -- PRI-主键，UNI-唯一键，MUL-外键
 column_comment as columnComment,  -- 字段中文名称
 column_type as columnType, -- 字段类型
 IS_NULLABLE as isNullLable -- 是否允许为空
 from information_schema.columns where table_schema = (select database()) and table_name = ('sys_role_dept') order by ordinal_position

2、TableVo接收sql查询得到的数据

package com.dtt.web.domain.vo;
import lombok.Data;

@Data
public class TableVo {
    public String columnName; // 字段名
    public String colDefault; // 默认值
    public String columnKey; // PRI-主键，UNI-唯一键，MUL-外键
    public String columnComment; // 字段中文名称
    public String columnType; // 字段类型
    public String isNullLable; // 是否为空  YES，NO
}

3、excel导出

注意：需要hutool依赖

@Test
public void exportTable(){
    String tableName = "ssa_store_info";
    SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
    List<TableVo> sysRoleDept = demoMapper.getList(tableName);
    List<Map<String, Object>> rows = sysRoleDept.stream().map(
        a -> {
            Map<String, Object> row = new LinkedHashMap<>();
            String PRI = "N"; // 主键
            String MUL = "N"; // 外键
            String UNI = "N"; // 唯一
            String defaultStr = "N";
            String isNotNull = "N"; // 是否非空
            if (a.getIsNullLable().equals("NO")) isNotNull = "Y";
            if (Strings.isNotBlank(a.getColDefault())) defaultStr = a.getColDefault();
            String columnKey = a.getColumnKey();
            if (columnKey.equals("PRI")) {
                PRI = "Y";
                UNI = "Y";
            }
            if (columnKey.equals("MUL")) MUL = "Y";
            if (columnKey.equals("UNI")) UNI = "Y";
            row.put("字段中文名", a.getColumnComment());
            row.put("字段名", a.getColumnName());
            row.put("数据类型", a.getColumnType());
            row.put("主键", PRI);
            row.put("外键", MUL);
            row.put("唯一", UNI);
            row.put("非空", isNotNull);
            row.put("缺省", defaultStr);
            row.put("描述", a.getColumnComment());
            return row;
        }
    ).collect(Collectors.toList());
    ExcelWriter writer = ExcelUtil.getWriter("e:/"+tableName+sdf.format(new Date())+".xlsx");
    // 微调一下每个列的宽度
    writer.setColumnWidth(0,16);
    writer.setColumnWidth(1,16);
    writer.setColumnWidth(2,16);
    writer.setColumnWidth(3,16);
    writer.setColumnWidth(4,16);
    writer.setColumnWidth(5,16);
    writer.setColumnWidth(6,16);
    writer.setColumnWidth(7,16);
    writer.setColumnWidth(8,16);
    //一次性写出内容，强制输出标题
    writer.write(rows, true);
    //关闭writer，释放内存
    writer.close();
    System.out.println();
}

4、导出案例