JDBC的扩展知识点总结

public void testJDBCTransaction() {
Connection conn = null;
try {
// 1.获取数据库连接
conn = JDBCUtils.getConnection();
// 2.开启事务
conn.setAutoCommit(false);
// 3.进行数据库操作

// 4.若没有异常，则提交事务
conn.commit();
} catch (Exception e) {
e.printStackTrace();
// 5.若有异常，则回滚事务
try {
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}} finally {
JDBCUtils.close(null, null, conn); }  }

package com.company.jdbcDemo;

import com.company.jdbcDemo.JDBCUtils;

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


public class AccountDemo {

    public static void main(String[] args) throws SQLException {
        //1.获取数据库连接对象
        Connection connection = JDBCUtils.getConnection();
        PreparedStatement ps = null;
        try {
            //2.开启事物--禁止自动提交
            connection.setAutoCommit(false);
            //-------------------------------------------------------------------
            //3.做具体的操作---执行sql语句
            //预编译
            String sql = "update account set balance=? where name=?";
            ps = connection.prepareStatement(sql);

            //给占位符赋值
            ps.setInt(1, 1000);
            ps.setString(2, "aa");
            //执行sql
            ps.executeUpdate();

            System.out.println(1 / 0);

            //给占位符赋值
            ps.setInt(1, 3000);
            ps.setString(2, "cc");
            //执行sql
            ps.executeUpdate();
            //-------------------------------------------------------------------
            //4.事务提交
            connection.commit();
        }catch (Exception e){
            e.printStackTrace();
            //5.事务回滚
            connection.rollback();
        }finally {
            //6.允许自动提交
            connection.setAutoCommit(true);
            //7.关闭资源----最后关闭资源
            JDBCUtils.close(ps,connection);

        }
    }
}

//1、创建数据源（数据库连接池）对象
DruidDataSource ds =new DruidDataSource();
//2、设置参数
//(1)设置基本参数
ds.setDriverClassName("com.mysql.jdbc.Driver");
ds.setUrl("jdbc:mysql://localhost:3306/test");
ds.setUsername("root");
ds.setPassword("mysql123");
//3、获取连接
Connection conn = ds.getConnection();
//如果这里没有关闭，就相当于没有还
conn.close();

// 创建配置文件druid.properties
url=jdbc:mysql://localhost:3306/0319db ?rewriteBatchedStatements=true
username=root
password=123456
driverClassName=com.mysql.jdbc.Driver

代码如下：
Properties pro = new Properties();
pro.load(TestDruid2.class.getClassLoader().getResourceAsStream("druid.properties"));
DataSource ds=
		DruidDataSourceFactory.createDataSource(pro);
Connection conn = ds.getConnection();

// druid.properties内容
url=jdbc:mysql://localhost:3306/demo
username=root
password=123321
driverClassName=com.mysql.jdbc.Driver

package com.company.jdbc2;

import com.company.jdbc.JDBCUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.junit.Test;

import java.sql.SQLException;
import java.util.List;


public class DBUtilsDemo {

    @Test
    public void test() throws SQLException {
        //1.创建操作对象
        QueryRunner queryRunner = new QueryRunner();
        //2.增，删，改是一个方法
        
        String sql = "insert into student(sid,sname,sage) values(?,?,?)";
        //返回值 ：有几条数据受到影响
        int i = queryRunner.update(JDBCUtils.getConnection(),
                sql, 10, "kongkong", 18);
        System.out.println("有" + i + "条数据受到影响");
    }

    @Test
    public void test2() throws SQLException {
        QueryRunner queryRunner = new QueryRunner();
        
        String sql = "select sid a,sname,sage from student where sid=?";
        //注意：类中的属性名一定要和字段名相同。如果不相同则需要在sql语句中使用别名
//        Student student = queryRunner.query(JDBCUtils.getConnection(), sql,
//                new BeanHandler<Student>(Student.class), 10);




        sql = "select sid a,sname,sage from student";
        List<Student> list = queryRunner.query(JDBCUtils.getConnection(), sql,
                new BeanListHandler<Student>(Student.class));

       for (Student s : list) {
           System.out.println(s);
       }
    }

}

jdbc:mysql://localhost:3306/Demo?rewriteBatchedStatements=true

package com.company.jdbc3;

import com.company.jdbc.JDBCUtils;
import org.junit.Test;

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


public class BatchDemo {

    
    @Test
    public void test2() throws SQLException {
        //1.获取数据库连接
        Connection connection = JDBCUtils.getConnection();
        //2.预编译
        PreparedStatement ps = connection.prepareStatement(
                "insert into student(sid,sname,sage) values(?,?,?)");
        //3.给占位符赋值
        for (int i = 1; i <= 100000 ; i++) {
            ps.setInt(1,i);
            ps.setString(2,"aaa"+i);
            ps.setInt(3,i);
            //添加到批处理中
            ps.addBatch();

            if (i % 1000 == 0){
                //执行sql
                ps.executeBatch();//执行批处理
                //清空批处理
                ps.clearBatch();
            }

        }
        //4.关资源
        JDBCUtils.close(ps,connection);
    }

    @Test
    public void test() throws SQLException {
        //1.获取数据库连接
        Connection connection = JDBCUtils.getConnection();
        //2.预编译
        PreparedStatement ps = connection.prepareStatement(
                "insert into student(sid,sname,sage) values(?,?,?)");
        //3.给占位符赋值
        for (int i = 1; i <= 100000 ; i++) {
            ps.setInt(1,i);
            ps.setString(2,"aaa"+i);
            ps.setInt(3,i);
            //执行sql
            ps.executeUpdate();
        }
        //4.关资源
        JDBCUtils.close(ps,connection);
    }
}