标准JDBC操作五步骤 + 自动提交事务

标准JDBC操作五步骤

package jdbc.sample;

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

/**
 * 标准JDBC操作五步骤
 */
public class StandardJDBCSample {
    public static void main(String[] args) {
        Connection conn = null;
        try {
            //1. 加载并注册JDBC驱动
                    //8.0
            Class.forName("com.mysql.cj.jdbc.Driver");
                 //5.0
            Class.forName("com.mysql.jdbc.Driver");
            //2. 创建数据库连接
                 //8.0
            conn = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/imooc?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&&allowPublicKeyRetrieval=true",
                    "root", "root"
            );
                 //5.0
            DriverManager.getConnection("jdbc:mysql://localhost:3306...","root","root");
            //3. 创建Statement对象
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("select * from employee where dname='研发部'");
            //4. 遍历查询结果
            while (rs.next()) {
                Integer eno = rs.getInt(1); //eno
                String ename = rs.getString("ename");
                Float salary = rs.getFloat("salary");
                String dname = rs.getString("dname");
                System.out.println(dname + "-" + eno + "-" + ename + "-" + salary);
            }
        }catch(Exception e){
            e.printStackTrace();
        }finally {
            try {//5. 关闭连接,释放资源
                if (conn != null && conn.isClosed() == false) {
 
                    conn.close();
                }
            }catch(Exception ex){
                ex.printStackTrace();
            }
        }

    }
}

自动提交事务

package jdbc.sample;

import jdbc.common.DbUtils;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Date;

/**
 * JDBC批处理
 */
public class BatchSample {
    //标准方式插入若干数据
    private static void tc1(){
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            long startTime = new Date().getTime();
            conn = DbUtils.getConnection();
            //JDBC默认使用自动提交模式
            conn.setAutoCommit(false);//关闭自动提交
            String sql = "insert into employee(eno,ename,salary,dname) values(?,?,?,?)";
            for (int i=100000;i<200000;i++){
//                if (i == 10) {
////                    throw new RuntimeException("插入失败");
//                }
                pstmt = conn.prepareStatement(sql);
                pstmt.setInt(1, i);
                pstmt.setString(2, "员工" + i);
                pstmt.setFloat(3, 4000f);
                pstmt.setString(4, "市场部");
                pstmt.executeUpdate();
            }
            conn.commit();//提交数据
            long endTime = new Date().getTime();
            System.out.println("tc1()执行时长：" + (endTime-startTime));
        } catch (Exception e) {
            e.printStackTrace();
            try {
                if(conn != null && !conn.isClosed()) {
                    conn.rollback();//回滚数据
                }
            }catch (SQLException ex){
                ex.printStackTrace();
            }
        } finally {
            DbUtils.closeConnection(null, pstmt, conn);
        }
    }


    //使用批处理插入若干数据
    private static void tc2(){
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            long startTime = new Date().getTime();
            conn = DbUtils.getConnection();
            //JDBC默认使用自动提交模式
            conn.setAutoCommit(false);//关闭自动提交
            String sql = "insert into employee(eno,ename,salary,dname) values(?,?,?,?)";
            pstmt = conn.prepareStatement(sql);
            for (int i=200000;i<300000;i++){
//                if (i == 10) {
////                    throw new RuntimeException("插入失败");
//                }
                pstmt.setInt(1, i);
                pstmt.setString(2, "员工" + i);
                pstmt.setFloat(3, 4000f);
                pstmt.setString(4, "市场部");
                pstmt.addBatch();//将参数加入批处理任务
//                pstmt.executeUpdate();对同一个对象进行操作所以注释
            }
            pstmt.executeBatch();//执行批处理任务(一次性打包 一下子全部发给mysql)
            conn.commit();//提交数据
            long endTime = new Date().getTime();
            System.out.println("tc2()执行时长：" + (endTime-startTime));
        } catch (Exception e) {
            e.printStackTrace();
            try {
                if(conn != null && !conn.isClosed()) {
                    conn.rollback();//回滚数据
                }
            }catch (SQLException ex){
                ex.printStackTrace();
            }
        } finally {
            DbUtils.closeConnection(null, pstmt, conn);
        }
    }


    public static void main(String[] args) {
        tc1();
        tc2();
    }
}