我想在不到一秒的时间内将大约 10K 条记录更新到 MySQL 数据库中。我写了下面的代码,大约需要 6-8 秒才能将记录列表更新到数据库中。
public void updateResultList(List<?> list) {
String user = "root";
String pass = "root";
String jdbcUrl = "jdbc:mysql://12.1.1.1/db_1?useSSL=false";
String driver = "com.mysql.jdbc.Driver";
PreparedStatement pstm = null;
try {
Class.forName(driver);
Connection myConn = DriverManager.getConnection(jdbcUrl, user, pass);
myConn.setAutoCommit(false);
for(int i=0; i<list.size(); i++) {
Object[] row = (Object[]) list.get(i);
int candidateID = Integer.valueOf(String.valueOf(row[0]));
String result = String.valueOf(row[14]);
int score = Integer.valueOf(String.valueOf(row[19]));
String uploadState = (String) row[20];
String sql = "UPDATE personal_info SET result = ?, score = ?, uploadState = ? "
+ " WHERE CandidateID = ?";
pstm = (PreparedStatement) myConn.prepareStatement(sql);
pstm.setString(1, result);
pstm.setInt(2, score);
pstm.setString(3, uploadState);
pstm.setInt(4, candidateID);
pstm.addBatch();
pstm.executeBatch();
}
myConn.commit();
myConn.setAutoCommit(true);
pstm.close();
myConn.close();
}
catch (Exception exc) {
exc.printStackTrace();
try {
throw new ServletException(exc);
} catch (ServletException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
请让我知道您对优化此代码以提高性能的意见。
最佳答案
首先,你只需要初始化一次prepareStatement
,你需要在for
循环之前初始化它
其次,你应该避免执行 pstm.executeBatch();
每次循环都会消耗更多的资源,你需要执行指定的数量,比如 100,500 或更多,也做不要只在for
循环外执行一次,因为它会消耗更多的内存资源
Class.forName(driver);
Connection myConn = DriverManager.getConnection(jdbcUrl, user, pass);
myConn.setAutoCommit(false);
String sql = "UPDATE personal_info SET result = ?, score = ?, uploadState = ? "
+ " WHERE CandidateID = ?";
pstm = (PreparedStatement) myConn.prepareStatement(sql);
for(int i=0; i<list.size(); i++) {
Object[] row = (Object[]) list.get(i);
int candidateID = Integer.valueOf(String.valueOf(row[0]));
String result = String.valueOf(row[14]);
int score = Integer.valueOf(String.valueOf(row[19]));
String uploadState = (String) row[20];
pstm.setString(1, result);
pstm.setInt(2, score);
pstm.setString(3, uploadState);
pstm.setInt(4, candidateID);
pstm.addBatch();
if(i%500==0){//execute when it meet a specified amount
pstm.executeBatch();
}
}
pstm.executeBatch();
myConn.commit();
myConn.setAutoCommit(true);
关于java - 如何在几毫秒内将数千条记录更新到 MySQL 数据库中,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50814572/