后端开发Druid数据库连接池,DbUtils.QueryRunner和DbUtils.closeQuietly的使用实例
Posted cls1277
tags:
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其实JDBC的操作在Druid和DbUtils的包里面都被封装好了
所以在建立连接的时候可以使用德鲁伊数据库连接池
数据库的CRUD操作可以用QueryRunner实现
连接的关闭可以使用closeQuietly实现
package com.cls1277.dbutils;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.cls1277.preparedstatement.customer.Customer;
import com.cls1277.utils.JDBCutils;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import org.junit.Test;
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.List;
import java.util.Properties;
public class QueryRunnerTest
// 德鲁伊数据连接池
public static Connection getConnection_Druid() throws Exception
Properties pros = new Properties();
InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("druid.properties");
pros.load(is);
DataSource source = DruidDataSourceFactory.createDataSource(pros);
Connection conn = source.getConnection();
return conn;
@Test
public void testInsert() throws Exception
QueryRunner runner = new QueryRunner();
Connection conn = JDBCutils.getConnection_Druid();
String sql = "insert into customers(name,email,birth)values(?,?,?)";
runner.update(conn, sql, "p", "p@qq.com", java.sql.Date.valueOf("1900-01-01"));
System.out.println("over");
//使用BeanHandler:查询一个记录,是ResultSetHandler接口的实现类
@Test
public void testQuery1()
Connection conn = null;
try
QueryRunner runner = new QueryRunner();
conn = JDBCutils.getConnection_Druid();
String sql = "select id,name,email,birth from customers where id = ?";
BeanHandler<Customer> handler = new BeanHandler<Customer>(Customer.class);
Customer customer = runner.query(conn, sql, handler, 1);
System.out.println(customer);
catch (Exception e)
e.printStackTrace();
finally
JDBCutils.closeResource(conn, null);
//BeanListHandler:查询多个记录
@Test
public void testQuery2()
Connection conn = null;
try
QueryRunner runner = new QueryRunner();
conn = JDBCutils.getConnection_Druid();
String sql = "select id,name,email,birth from customers where id < ?";
BeanListHandler<Customer> handler = new BeanListHandler<Customer>(Customer.class);
List<Customer> customers = runner.query(conn, sql, handler, 20);
for(Customer customer:customers)
System.out.println(customer);
catch (Exception e)
e.printStackTrace();
finally
JDBCutils.closeResource(conn, null);
//ScalarHandler
@Test
public void testQuery3()
Connection conn = null;
try
QueryRunner runner = new QueryRunner();
conn = JDBCutils.getConnection_Druid();
String sql = "select count(*) from customers";
ScalarHandler handler = new ScalarHandler<>();
Long count = (Long) runner.query(conn, sql, handler);
System.out.println(count);
catch (Exception e)
e.printStackTrace();
finally
JDBCutils.closeResource(conn, null);
//DbUtils提供的关闭方法
public static void closeResource_DbUtils(Connection conn, PreparedStatement ps, ResultSet rs)
// try
// DbUtils.close(conn);
// catch (SQLException e)
// throw new RuntimeException(e);
//
// try
// DbUtils.close(ps);
// catch (SQLException e)
// throw new RuntimeException(e);
//
// try
// DbUtils.close(rs);
// catch (SQLException e)
// throw new RuntimeException(e);
//
DbUtils.closeQuietly(conn);
DbUtils.closeQuietly(ps);
DbUtils.closeQuietly(rs);
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