poi之大数据量导出

谁践踏了优雅 2022-09-29 06:10 202阅读 0赞

<dependencies>
    		<dependency>
    			<groupId>dom4j</groupId>
    			<artifactId>dom4j</artifactId>
    			<version>1.6.1</version>
    		</dependency>
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>5.1.35</version>
    		</dependency>
    		<dependency>
    			<groupId>org.apache.poi</groupId>
    			<artifactId>poi</artifactId>
    			<version>3.10-FINAL</version>
    		</dependency>
    		<dependency>
    			<groupId>org.apache.poi</groupId>
    			<artifactId>poi-ooxml</artifactId>
    			<version>3.10-FINAL</version>
    		</dependency>
    
    		<dependency>
    			<groupId>org.apache.poi</groupId>
    			<artifactId>poi-ooxml-schemas</artifactId>
    			<version>3.10-FINAL</version>
    		</dependency>
    		<dependency>
    			<groupId>org.apache.xmlbeans</groupId>
    			<artifactId>xmlbeans</artifactId>
    			<version>2.3.0</version>
    		</dependency>
    
    	</dependencies>

package com.tanlei.test.export;
    
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.lang.management.ManagementFactory;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.ResultSetMetaData;
    import java.sql.SQLException;
    import java.sql.Statement;
    
    import org.apache.poi.ss.usermodel.Cell;
    import org.apache.poi.ss.usermodel.Row;
    import org.apache.poi.ss.usermodel.Sheet;
    import org.apache.poi.ss.usermodel.Workbook;
    import org.apache.poi.xssf.streaming.SXSSFWorkbook;
    
    public class BigDataExport {
    
    	public static void main(String[] args) throws Exception {
    		String name = ManagementFactory.getRuntimeMXBean().getName();
    		System.out.println(name);
    		// get pid
    		String pid = name.split("@")[0];
    		System.out.println("Pid is:" + pid);
    
    		BigDataExport tm = new BigDataExport();
    		tm.jdbcex(true);
    		Thread.sleep(1000 * 40);
    	}
    
    	public void jdbcex(boolean isClose) throws InstantiationException, IllegalAccessException, ClassNotFoundException,
    			SQLException, IOException, InterruptedException {
    
    		String xlsFile = "f:/poiSXXFSBigData.xlsx"; // 输出文件
    		// 内存中只创建100个对象，写临时文件，当超过100条，就将内存中不用的对象释放。
    		Workbook wb = new SXSSFWorkbook(100); // 关键语句
    		Sheet sheet = null; // 工作表对象
    		Row nRow = null; // 行对象
    		Cell nCell = null; // 列对象
    
    		// 使用jdbc链接数据库
    		Class.forName("com.mysql.jdbc.Driver").newInstance();
    		String url = "jdbc:mysql://xxx.xxx.xxx.xxx/dbname?useUnicode=true&allowMultiQueries=true&characterEncoding=UTF-8&useFastDateParsing=false&zeroDateTimeBehavior=convertToNull";
    		String user = "root";
    		String password = "root1234";
    		// 获取数据库连接
    		Connection conn = DriverManager.getConnection(url, user, password);
    		Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
    		String sql = "select * from tb_applyflow_rpt"; // 100万+测试数据
    		ResultSet rs = stmt.executeQuery(sql);
    
    		ResultSetMetaData rsmd = rs.getMetaData();
    		long startTime = System.currentTimeMillis(); // 开始时间
    		System.out.println("strat execute time: " + startTime);
    
    		int rowNo = 0; // 总行号
    		int pageRowNo = 0; // 页行号
    
    		while (rs.next()) {
    			// 打印300000条后切换到下个工作表，可根据需要自行拓展，2百万，3百万...数据一样操作，只要不超过1048576就可以
    			if (rowNo % 300000 == 0) {
    				System.out.println("Current Sheet:" + rowNo / 300000);
    				sheet = wb.createSheet("我的第" + (rowNo / 300000) + "个工作簿");// 建立新的sheet对象
    				sheet = wb.getSheetAt(rowNo / 300000); // 动态指定当前的工作表
    				pageRowNo = 0; // 每当新建了工作表就将当前工作表的行号重置为0
    			}
    			rowNo++;
    			nRow = sheet.createRow(pageRowNo++); // 新建行对象
    
    			// 打印每行，每行有6列数据 rsmd.getColumnCount()==6 --- 列属性的个数
    			for (int j = 0; j < rsmd.getColumnCount(); j++) {
    				nCell = nRow.createCell(j);
    				nCell.setCellValue(rs.getString(j + 1));
    			}
    
    			if (rowNo % 10000 == 0) {
    				System.out.println("row no: " + rowNo);
    			}
    			// Thread.sleep(1); //休息一下，防止对CPU占用，其实影响不大
    		}
    
    		long finishedTime = System.currentTimeMillis(); // 处理完成时间
    		System.out.println("finished execute  time: " + (finishedTime - startTime) / 1000 + "m");
    
    		FileOutputStream fOut = new FileOutputStream(xlsFile);
    		wb.write(fOut);
    		fOut.flush(); // 刷新缓冲区
    		fOut.close();
    
    		long stopTime = System.currentTimeMillis(); // 写文件时间
    		System.out.println("write xlsx file time: " + (stopTime - startTime) / 1000 + "m");
    
    		if (isClose) {
    			this.close(rs, stmt, conn);
    		}
    	}
    
    	// 执行关闭流的操作
    	private void close(ResultSet rs, Statement stmt, Connection conn) throws SQLException {
    		rs.close();
    		stmt.close();
    		conn.close();
    	}
    }