我在学习 JDBC 批处理时， 为比较 Statement, PreparedStatement 和 JDBC Batch 操作之间的效率，写一个例子：向数据库中插入 100,000 条记录，并记录消耗的时间。然后分别用这三种方式实现，可每次测试的结果却都是几乎相同没变化，请教大神这是为什么？
import org.junit.Test;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Statement;
public class BatchTest {
/**
* 使用 Statement 进行批处理操作
*/
@Test
public void testBatchWithStatement(){
Connection connection = null;
Statement statement;
String sql;
try {
connection = JDBCUtils.getConnection();
JDBCUtils.beginTx(connection);
statement = connection.createStatement();
long start = System.currentTimeMillis();
for (int i = 0; i < 100000; i++) {
sql = "INSERT INTO batch VALUES(" + i +")";
statement.executeUpdate(sql);
}
long end = System.currentTimeMillis();
System.out.println(end - start);
JDBCUtils.commit(connection);
} catch (Exception e) {
e.printStackTrace();
JDBCUtils.rollback(connection);
}
}
/**
* 使用 PreparedStatement 进行批处理操作
*/
@Test
public void testBatchWithPreparedStatement(){
Connection connection = null;
PreparedStatement statement;
String sql;
try {
connection = JDBCUtils.getConnection();
JDBCUtils.beginTx(connection);
sql = "INSERT INTO batch VALUES(?)";
statement = connection.prepareStatement(sql);
long start = System.currentTimeMillis();
for (int i = 0; i < 100000; i++) {
statement.setInt(1, i + 1);
statement.executeUpdate();
}
long end = System.currentTimeMillis();
System.out.println(end - start);
JDBCUtils.commit(connection);
} catch (Exception e) {
e.printStackTrace();
JDBCUtils.rollback(connection);
}
}
/**
* 使用 Batch 进行批处理操作
*/
@Test
public void testBatch(){
Connection connection = null;
PreparedStatement statement;
String sql;
try {
connection = JDBCUtils.getConnection();
JDBCUtils.beginTx(connection);
sql = "INSERT INTO batch VALUES(?)";
statement = connection.prepareStatement(sql);
long start = System.currentTimeMillis();
for (int i = 0; i < 100000; i++) {
statement.setInt(1, i + 1);
statement.addBatch();
if ((i + 1) % 500 == 0){
statement.executeBatch();
statement.clearBatch();
}
}
if (100000 % 300 != 0){
statement.executeBatch();
statement.clearBatch();
}
long end = System.currentTimeMillis();
System.out.println(end - start);
JDBCUtils.commit(connection);
} catch (Exception e) {
e.printStackTrace();
JDBCUtils.rollback(connection);
}
}
}
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