使用JDBC連接MySQL數(shù)據(jù)庫進行數(shù)據(jù)插入的時候,特別是大批量數(shù)據(jù)連續(xù)插入(10W+),如何提高效率呢?
在JDBC編程接口中Statement 有兩個方法特別值得注意:
void addBatch() throws SQLException
Adds a set of parameters to this PreparedStatement object's batch of commands.
int[] executeBatch() throws SQLException
Submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts. The int elements of the array that is returned are ordered to correspond to the commands in the batch, which are ordered according to the order in which they were added to the batch.
通過使用addBatch()和executeBatch()這一對方法可以實現(xiàn)批量處理數(shù)據(jù)。
不過值得注意的是,首先需要在數(shù)據(jù)庫鏈接中設(shè)置手動提交,connection.setAutoCommit(false),然后在執(zhí)行Statement之后執(zhí)行connection.commit()。
package cyl.demo.ipsearcher;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class DbStoreHelper {
private String insert_sql;
private String charset;
private boolean debug;
private String connectStr;
private String username;
private String password;
public DbStoreHelper() {
connectStr = "jdbc:mysql://localhost:3306/db_ip";
// connectStr += "?useServerPrepStmts=falserewriteBatchedStatements=true";
insert_sql = "INSERT INTO tb_ipinfos (iplong1,iplong2,ipstr1,ipstr2,ipdesc) VALUES (?,?,?,?,?)";
charset = "gbk";
debug = true;
username = "root";
password = "***";
}
public void storeToDb(String srcFile) throws IOException {
BufferedReader bfr = new BufferedReader(new InputStreamReader(new FileInputStream(srcFile), charset));
try {
doStore(bfr);
} catch (Exception e) {
e.printStackTrace();
} finally {
bfr.close();
}
}
private void doStore(BufferedReader bfr) throws ClassNotFoundException, SQLException, IOException {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(connectStr, username,password);
conn.setAutoCommit(false); // 設(shè)置手動提交
int count = 0;
PreparedStatement psts = conn.prepareStatement(insert_sql);
String line = null;
while (null != (line = bfr.readLine())) {
String[] infos = line.split(";");
if (infos.length 5) continue;
if (debug) {
System.out.println(line);
}
psts.setLong(1, Long.valueOf(infos[0]));
psts.setLong(2, Long.valueOf(infos[1]));
psts.setString(3, infos[2]);
psts.setString(4, infos[3]);
psts.setString(5, infos[4]);
psts.addBatch(); // 加入批量處理
count++;
}
psts.executeBatch(); // 執(zhí)行批量處理
conn.commit(); // 提交
System.out.println("All down : " + count);
conn.close();
}
}
執(zhí)行完成以后:
All down : 103498
Convert finished.
All spend time/s : 47
一共10W+,執(zhí)行時間一共花費 47 秒.
這個效率仍然不高,似乎沒有達到想要的效果,需要進一步改進。
在MySQL JDBC連接字符串中還可以加入?yún)?shù),
rewriteBatchedStatements=true,mysql默認關(guān)閉了batch處理,通過此參數(shù)進行打開,這個參數(shù)可以重寫向數(shù)據(jù)庫提交的SQL語句。
useServerPrepStmts=false,如果不開啟(useServerPrepStmts=false),使用com.mysql.jdbc.PreparedStatement進行本地SQL拼裝,最后送到db上就是已經(jīng)替換了?后的最終SQL.
在此稍加改進,連接字符串中加入下面語句(代碼構(gòu)造方法中去掉注釋):
connectStr += "?useServerPrepStmts=falserewriteBatchedStatements=true";
再次執(zhí)行如下:
All down : 103498
Convert finished.
All spend time/s : 10
同樣的數(shù)據(jù)量,這次執(zhí)行只花費了10秒 ,處理效率大大提高.
以上就是本文的全部內(nèi)容,希望對大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
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