Statement與PreparedStatement的區別

時間 2019-12-22

標籤 statement preparedstatement 區別简体版

原文原文鏈接

Statement與PreparedStatement的區別

原創 2014年04月18日 10:43:11java

9305

1:建立時的區別： mysql

    Statement statement = conn.createStatement();
    PreparedStatement preStatement = conn.prepareStatement(sql);
    執行的時候:
    ResultSet rSet = statement.executeQuery(sql);
    ResultSet pSet = preStatement.executeQuery();sql

由上能夠看出，PreparedStatement有預編譯的過程，已經綁定sql，以後不管執行多少遍，都不會再去進行編譯，數據庫

而 statement 不一樣，若是執行多變，則相應的就要編譯多少遍sql，因此從這點看，preStatement 的效率會比 Statement要高一些安全

[java] view plain copyapp

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
public class JDBCTest {
public static void main(String[] args) throws Exception {
//1 加載數據庫驅動
Class.forName("com.mysql.jdbc.Driver");
//2 獲取數據庫鏈接
String url = "jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8";
String user = "root";
String password = "root";
Connection conn = DriverManager.getConnection(url, user, password);
//3 建立一個Statement
String sql = "select id,loginName,email from user where id=";
String tempSql;
int count = 1000;
long time = System.currentTimeMillis();
for(int i=0 ;i<count ;i++){
Statement statement = conn.createStatement();
tempSql=sql+(int) (Math.random() * 100);
ResultSet rSet = statement.executeQuery(tempSql);
statement.close();
}
System.out.println("statement cost:" + (System.currentTimeMillis() - time));
String psql = "select id,loginName,email from user where id=?";
time = System.currentTimeMillis();
for (int i = 0; i < count; i++) {
int id=(int) (Math.random() * 100);
PreparedStatement preStatement = conn.prepareStatement(psql);
preStatement.setLong(1, new Long(id));
ResultSet pSet = preStatement.executeQuery();
preStatement.close();
}
System.out.println("preStatement cost:" + (System.currentTimeMillis() - time));
conn.close();
}
}