java 读取excel

java 操作读取excel中的内容

首先创建一个maven工程,引入一下依赖：

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.2.4</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.72</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

创建一个xlsx(这里只是截图)

创建一个普通对象，和xlsx字段名称对应起来

package com.example.demo;

import com.alibaba.excel.annotation.ExcelIgnore;
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.metadata.BaseRowModel;
import lombok.Data;

import javax.sql.rowset.BaseRowSet;

/**
 * @Author: heiye
 * @Date: 2021/08/23/20:11
 * @Description:
 */
@Data
public class UserInfo extends BaseRowModel {

    @ExcelProperty(index=0)	//这个注解代表的是xlsx中的字段名称 ,index代表的是第几个，默认从0开始
    private String id;

    @ExcelProperty(index  =1)
    private String date;
}

创建一个DemoDataListener

package com.example.demo;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.fastjson.JSON;
import lombok.val;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * @Author: heiye
 * @Date: 2021/08/23/20:22
 * @Description:
 */
// 有个很重要的点 DemoDataListener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去
public class DemoDataListener extends AnalysisEventListener<UserInfo> {

    /**
     * 每隔5条存储数据库，实际使用中可以3000条，然后清理list ，方便内存回收
     */
    private static final int BATCH_COUNT = 6;

    List<UserInfo> list = new ArrayList<UserInfo>();

    /**
     * 这个每一条数据解析都会来调用
     *
     * @param data
     * @param context
     */
    @Override
    public void invoke(UserInfo data, AnalysisContext context) {
        System.out.println(data.getId()+'\t'+data.getDate());

        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        Connection connection = null;
        try {
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/chenhao?serverTimezone=UTC","root","");
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        System.out.println(connection.toString());
        String sql = "update test set toilet_date=? where serial=?";
        PreparedStatement preparedStatement = null;
        try {
            preparedStatement = connection.prepareStatement(sql);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        try {
            preparedStatement.setObject(1, data.getDate());
            preparedStatement.setObject(2,data.getId());
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }

        try {
            preparedStatement.executeUpdate();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        try {
            preparedStatement.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        try {
            connection.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        System.out.println("解析到一条数据:" + JSON.toJSONString(data));
        val str=JSON.toJSONString(data);
        list.add(data);
        // 达到BATCH_COUNT了，需要去存储一次数据库，防止数据几万条数据在内存，容易OOM
        if (list.size() >= BATCH_COUNT) {
            // 存储完成清理 list
            list.clear();
        }
    }

    /**
     * 所有数据解析完成了 都会来调用
     *
     * @param context
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        System.out.println("最后一次解析了" + list.size() + "条数据！");
        System.out.println("所有数据解析完成！");
    }


    public List<UserInfo> returnList() {
        return list;
    }
}

创建EasyExcelRead.java

package com.example.demo;

import com.alibaba.excel.EasyExcel;
import org.testng.annotations.Test;

import java.io.File;

/**
 * @Author: heiye
 * @Date: 2021/08/23/20:22
 * @Description:
 */
public class EasyExcelRead {

  /**
   * 读取的excel所在的路径
   */
  private static final String PATH = "D:\\";

  /**
   * 最简单的读
   * 有个很重要的点 DemoDataListener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去
   * 需要指定读用哪个class去读，然后读取第一个sheet 文件流会自动关闭
   */
  @Test
  public void simpleRead() {

    // 路径的文件名 - 即文件所在位置，通过它能找到这个文件
    String fileName = PATH + File.separator + "22.xlsx";

    /*
     * fileName - 文件名(包含路径)
     * DemoData.class - 实体类的反射对象
     * new DemoDataListener() - 监听器
     * sheetName - 工作表的名称
     * data() - 数据部分（实体类集合）
     */
    EasyExcel.read(fileName, UserInfo.class, new DemoDataListener()).sheet().doRead();
  }
}

主类

package com.example.demo;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelReader;
import com.alibaba.excel.metadata.Sheet;
import com.alibaba.excel.read.metadata.ReadSheet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;

@SpringBootApplication
public class DemoApplication {
    static EasyExcelRead easyExcelRead=new EasyExcelRead();

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
        easyExcelRead.simpleRead();
    }
}