Java JDBC高级特性

1、JDBC批处理

实际开发中需要向数据库发送多条SQL语句，这时，如果逐条执行SQL语句，效率会很低，因此可以使用JDBC提供的批处理机制。Statement和PreparedStatemen都实现了批处理。测试表结构如下：

Statement批处理程序示例

package server;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import com.mysql.jdbc.PreparedStatement;

public class DemoJDBC {
public static void main(String[] args) throws Exception {
// 加载驱动类
Class.forName("com.mysql.jdbc.Driver");

// 通过DriverManager获取数据库连接
String url = "jdbc:mysql://192.168.1.150/test";
String user = "teamtalk";
String password = "123456";
Connection connection = (Connection) DriverManager.getConnection(
url, user, password);

String sql1 = "DROP TABLE IF EXISTS people";
String sql2 = "CREATE TABLE people(id int, name varchar(20))";
String sql3 = "INSERT people VALUES(2, 'hdu')";
String sql4 = "UPDATE people SET id = 1";
Statement statement = (Statement) connection.createStatement();
statement.addBatch(sql1);
statement.addBatch(sql2);
statement.addBatch(sql3);
statement.addBatch(sql4);
statement.executeBatch();

ResultSet resultSet = statement.executeQuery("SELECT * from people");
while (resultSet.next()) {
System.out.println(resultSet.getString(1) + " " + resultSet.getString(2));
}
}
}

PreparedStatement批处理

package server;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import com.mysql.jdbc.PreparedStatement;

public class DemoJDBC {
public static void main(String[] args) throws Exception {
// 加载驱动类
Class.forName("com.mysql.jdbc.Driver");

// 通过DriverManager获取数据库连接
String url = "jdbc:mysql://192.168.1.150/test";
String user = "teamtalk";
String password = "123456";
Connection connection = (Connection) DriverManager.getConnection(
url, user, password);

PreparedStatement statement = (PreparedStatement) connection.prepareStatement("INSERT people VALUES(?,?)");
for (int i = 1; i < 4; i++) {
statement.setInt(1, i);
statement.setString(2, "hdu" + i);
statement.addBatch();
}
statement.executeBatch();

ResultSet resultSet = statement.executeQuery("SELECT * from people");
while (resultSet.next()) {
System.out.println(resultSet.getString(1) + " " + resultSet.getString(2));
}
}
}

2、JDBC处理事务

针对JDBC处理事务的操作，在Connection接口中，提供了3个相关的方法，具体如下：

1 setAutoCommit(boolean autoCommit); // 设置是否自动提交事务
2 commit(); // 提交事务
3 rollback(); // 撤销事务

将setAutoCommit()方法参数设置为false后，事务必须使用conn.commit()方法提交，而事务回滚不一定显式执行conn.rollback()。如果程序最后没有执行conn.commit()，事务也会回滚，一般是直接抛出异常，终止程序的正常执行。因此，通常情况下，会conn.rollback()语句放在catch语句块执行。

package demo.jdbc;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.Statement;

public class FirstJDBC {
public static void main(String[] args) throws ClassNotFoundException, SQLException, InterruptedException {
Connection connection = null;
try {
// 加载驱动类
Class.forName("com.mysql.jdbc.Driver");

// 通过DriverManager获取数据库连接
String url = "jdbc:mysql://192.168.1.150/test";
String user = "teamtalk";
String password = "123456";
connection = (Connection) DriverManager.getConnection(
url, user, password);
// 关闭事务的自动提交
connection.setAutoCommit(false);

Statement statement = (Statement) connection.createStatement();
PreparedStatement statement1 = (PreparedStatement) connection.prepareStatement("INSERT people VALUES(?, ?)");
PreparedStatement statement2 = (PreparedStatement) connection.prepareStatement("INSERT people VALUES(?, ?)");

statement1.setInt(1, 1);
statement1.setString(2, "hdu1");
statement2.setInt(1, 2);
statement2.setString(2, "hdu2");

statement1.executeUpdate();
statement2.executeUpdate();

ResultSet resultSet = statement.executeQuery("SELECT * from people");
while (resultSet.next()) {
System.out.println(resultSet.getString(1) + " " + resultSet.getString(2));
}
}
catch (Exception e) {
// 回滚事务
connection.rollback();
e.printStackTrace();
}
}
}

猜你喜欢