前言
MySQL是一款常用的开源数据库产品,通常也是免费数据库的首选。查了一下NPM列表,发现Nodejs有13库可以访问MySQL,felixge/node-mysql似乎是最受关注项目,我也决定尝试用一下。
要注意名字,”felixge/node-mysql”非”node-mysql”,安装部分会介绍这个小插曲!
目录
node-mysql介绍
建立MySQL测试库
node-mysql安装
node-mysql使用
1. node-mysql介绍
felixge/node-mysql是一个纯nodejs的用javascript实现的一个MySQL客户端程序。felixge/node-mysql封装了Nodejs对MySQL的基本操作,100% MIT公共许可证。
项目地址:https://github.com/felixge/node-mysql
2. 建立MySQL测试库
本地创建MySQL测试库:nodejs
~ mysql -uroot -p
mysql> CREATE DATABASE nodejs;
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| nodejs |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)
mysql> GRANT ALL ON nodejs.* to nodejs@'%' IDENTIFIED BY 'nodejs';
mysql> GRANT ALL ON nodejs.* to nodejs@localhost IDENTIFIED BY 'nodejs';
重新登陆MySQL
C:\Users\Administrator>mysql -unodejs -p
Enter password: ******
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| nodejs |
| test |
+--------------------+
3 rows in set (0.00 sec)
mysql> USE nodejs
Database changed
新建一个user表
CREATE TABLE t_user(
id INT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(16) NOT NULL ,
create_date TIMESTAMP NULL DEFAULT now()
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE UNIQUE INDEX t_quiz_IDX_0 on t_user(name);
mysql> SHOW TABLES;
+------------------+
| Tables_in_nodejs |
+------------------+
| t_user |
+------------------+
1 row in set (0.04 sec)
3. node-mysql安装
我的系统环境
win7 64bit
Nodejs:v0.10.5
Npm:1.2.19
MySQL:Server version: 5.6.11 MySQL Community Server (GPL)
创建工程:nodejs-node-mysql
~ D:\workspace\javascript>mkdir nodejs-node-mysql
~ D:\workspace\javascript>cd nodejs-node-mysql
~ D:\workspace\javascript\nodejs-node-mysql>npm install node-mysql
[email protected] node_modules\node-mysql
└── [email protected] ([email protected], [email protected])
这里有一个小插曲
安装“node-mysql”后,打开package.json文件发现,这个项目地址是
https://github.com/redblaze/node-mysql.git
从依赖关系可以看到,它依赖于mysql库,是对felixge/node-mysql的封装。
node-mysql1
由于这个项目star是0,fork也是0. 所以,我也不准备花时间测试了,重新安装felixge/node-mysql的包。
重新安装node-mysql
~ D:\workspace\javascript\nodejs-node-mysql>rm -rf node_modules
~ D:\workspace\javascript\nodejs-node-mysql>npm install [email protected]
npm http GET https://registry.npmjs.org/mysql/2.0.0-alpha9
npm http 200 https://registry.npmjs.org/mysql/2.0.0-alpha9
npm http GET https://registry.npmjs.org/mysql/-/mysql-2.0.0-alpha9.tgz
npm http 200 https://registry.npmjs.org/mysql/-/mysql-2.0.0-alpha9.tgz
npm http GET https://registry.npmjs.org/require-all/0.0.3
npm http GET https://registry.npmjs.org/bignumber.js/1.0.1
npm http 304 https://registry.npmjs.org/require-all/0.0.3
npm http 304 https://registry.npmjs.org/bignumber.js/1.0.1
[email protected] node_modules\mysql
这回就对了,继续下面的开发!
创建node程序启动文件:app.js
第一个测试
~ vi app.js
var mysql = require('mysql');
var conn = mysql.createConnection({
host: 'localhost',
user: 'nodejs',
password: 'nodejs',
database:'nodejs',
port: 3306
});
conn.connect();
conn.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
if (err) throw err;
console.log('The solution is: ', rows[0].solution);
});
conn.end();
运行node
~ D:\workspace\javascript\nodejs-node-mysql>node app.js
The solution is: 2
这样我们就让Nodejs连接上了MySQL。
4. node-mysql使用
下面我们要对node-mysql的API进行常用的测试。
表新删改查
连接池配置
MySQL断线重连
连接池超时测试
1). 表新删改查修改app.js
~ vi app.js
var mysql = require('mysql');
var conn = mysql.createConnection({
host: 'localhost',
user: 'nodejs',
password: 'nodejs',
database: 'nodejs',
port: 3306
});
conn.connect();
var insertSQL = 'insert into t_user(name) values("conan"),("fens.me")';
var selectSQL = 'select * from t_user limit 10';
var deleteSQL = 'delete from t_user';
var updateSQL = 'update t_user set name="conan update" where name="conan"';
//delete
conn.query(deleteSQL, function (err0, res0) {
if (err0) console.log(err0);
console.log("DELETE Return ==> ");
console.log(res0);
//insert
conn.query(insertSQL, function (err1, res1) {
if (err1) console.log(err1);
console.log("INSERT Return ==> ");
console.log(res1);
//query
conn.query(selectSQL, function (err2, rows) {
if (err2) console.log(err2);
console.log("SELECT ==> ");
for (var i in rows) {
console.log(rows[i]);
}
//update
conn.query(updateSQL, function (err3, res3) {
if (err3) console.log(err3);
console.log("UPDATE Return ==> ");
console.log(res3);
//query
conn.query(selectSQL, function (err4, rows2) {
if (err4) console.log(err4);
console.log("SELECT ==> ");
for (var i in rows2) {
console.log(rows2[i]);
}
});
});
});
});
});
//conn.end();
控制台输出:
D:\workspace\javascript\nodejs-node-mysql>node app.js
DELETE Return ==>
{ fieldCount: 0,
affectedRows: 2,
insertId: 0,
serverStatus: 34,
warningCount: 0,
message: '',
protocol41: true,
changedRows: 0 }
INSERT Return ==>
{ fieldCount: 0,
affectedRows: 2,
insertId: 33,
serverStatus: 2,
warningCount: 0,
message: '&Records: 2 Duplicates: 0 Warnings: 0',
protocol41: true,
changedRows: 0 }
SELECT ==>
{ id: 33,
name: 'conan',
create_date: Wed Sep 11 2013 12:09:15 GMT+0800 (中国标准时间) }
{ id: 34,
name: 'fens.me',
create_date: Wed Sep 11 2013 12:09:15 GMT+0800 (中国标准时间) }
UPDATE Return ==>
{ fieldCount: 0,
affectedRows: 1,
insertId: 0,
serverStatus: 2,
warningCount: 0,
message: '(Rows matched: 1 Changed: 1 Warnings: 0',
protocol41: true,
changedRows: 1 }
SELECT ==>
{ id: 33,
name: 'conan update',
create_date: Wed Sep 11 2013 12:09:15 GMT+0800 (中国标准时间) }
{ id: 34,
name: 'fens.me',
create_date: Wed Sep 11 2013 12:09:15 GMT+0800 (中国标准时间) }
由于node的异步的,上面是一个连续的操作,代码会被写的支离破碎。我们可以通过async库对上面代码进行封装,请参考文章:Nodejs异步流程控制Async
2). 连接池配置
增加文件:app-pooling.js
~ vi app-pooling.js
var mysql = require('mysql');
var pool = mysql.createPool({
host: 'localhost',
user: 'nodejs',
password: 'nodejs',
database: 'nodejs',
port: 3306
});
var selectSQL = 'select * from t_user limit 10';
pool.getConnection(function (err, conn) {
if (err) console.log("POOL ==> " + err);
conn.query(selectSQL,function(err,rows){
if (err) console.log(err);
console.log("SELECT ==> ");
for (var i in rows) {
console.log(rows[i]);
}
conn.release();
});
});
控制台输出:
D:\workspace\javascript\nodejs-node-mysql>node app-pooling.js
SELECT ==>
{ id: 39,
name: 'conan update',
create_date: Wed Sep 11 2013 13:41:18 GMT+0800 (中国标准时间) }
{ id: 40,
name: 'fens.me',
create_date: Wed Sep 11 2013 13:41:18 GMT+0800 (中国标准时间) }
3). MySQL断线重连
分别模拟3种错误
a.登陆密码错误
b.数据库宕机
c.数据库连接超时
新增文件:app-reconnect.js
~ vi app-reconnect.js
var mysql = require('mysql');
var conn;
function handleError () {
conn = mysql.createConnection({
host: 'localhost',
user: 'nodejs',
password: 'nodejs',
database: 'nodejs',
port: 3306
});
//连接错误,2秒重试
conn.connect(function (err) {
if (err) {
console.log('error when connecting to db:', err);
setTimeout(handleError , 2000);
}
});
conn.on('error', function (err) {
console.log('db error', err);
// 如果是连接断开,自动重新连接
if (err.code === 'PROTOCOL_CONNECTION_LOST') {
handleError();
} else {
throw err;
}
});
}
handleError();
a. 模拟密码错误
修改password: ‘nodejs11'
控制台输出。
D:\workspace\javascript\nodejs-node-mysql>node app-reconnect.js
error when connecting to db: { [Error: ER_ACCESS_DENIED_ERROR: Access denied for user 'nodejs'@'localhost' (using pass
rd: YES)]
code: 'ER_ACCESS_DENIED_ERROR',
errno: 1045,
sqlState: '28000',
fatal: true }
error when connecting to db: { [Error: ER_ACCESS_DENIED_ERROR: Access denied for user 'nodejs'@'localhost' (using pass
rd: YES)]
code: 'ER_ACCESS_DENIED_ERROR',
errno: 1045,
sqlState: '28000',
fatal: true }
b. 模拟数据库宕机正常启动node,然后杀掉mysqld的进程。
控制台输出。
D:\workspace\javascript\nodejs-node-mysql>node app-reconnect.js
db error { [Error: read ECONNRESET]
code: 'ECONNRESET',
errno: 'ECONNRESET',
syscall: 'read',
fatal: true }
Error: read ECONNRESET
at errnoException (net.js:884:11)
at TCP.onread (net.js:539:19)
这个异常,直接导致node程序被杀死!
c. 模拟连接超时,PROTOCOL_CONNECTION_LOST切换到root账户, 修改MySQL的wait_timeout参数,设置为10毫秒超时。
~ mysql -uroot -p
mysql> show variables like 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout | 28800 |
+---------------+-------+
1 row in set (0.00 sec)
mysql> set global wait_timeout=10;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout | 10 |
+---------------+-------+
1 row in set (0.00 sec)
修改文件:app-reconnection.js,在最后增加代码
~ vi app-reconnection.js
function query(){
console.log(new Date());
var sql = "show variables like 'wait_timeout'";
conn.query(sql, function (err, res) {
console.log(res);
});
}
query();
setInterval(query, 15*1000);
程序会每融15秒,做一次查询。
控制台输出
D:\workspace\javascript\nodejs-node-mysql>node app-reconnect.js
Wed Sep 11 2013 15:21:14 GMT+0800 (中国标准时间)
[ { Variable_name: 'wait_timeout', Value: '10' } ]
db error { [Error: Connection lost: The server closed the connection.] fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }
Wed Sep 11 2013 15:21:28 GMT+0800 (中国标准时间)
[ { Variable_name: 'wait_timeout', Value: '10' } ]
db error { [Error: Connection lost: The server closed the connection.] fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }
Wed Sep 11 2013 15:21:43 GMT+0800 (中国标准时间)
[ { Variable_name: 'wait_timeout', Value: '10' } ]
我们自己的程序捕获了“PROTOCOL_CONNECTION_LOST”异常,并自动的实现了数据库重连。
4). MySQL连接池的超时测试
针对wait_timeout问题,我们再对连接做一下测试。
修改app-pooling.js文件
var mysql = require('mysql');
var pool = mysql.createPool({
host: 'localhost',
user: 'nodejs',
password: 'nodejs',
database: 'nodejs',
port: 3306
});
var selectSQL ="show variables like 'wait_timeout'";
pool.getConnection(function (err, conn) {
if (err) console.log("POOL ==> " + err);
function query(){
conn.query(selectSQL, function (err, res) {
console.log(new Date());
console.log(res);
conn.release();
});
}
query();
setInterval(query, 5000);
});
控制台输出:
D:\workspace\javascript\nodejs-node-mysql>node app-pooling.js
Wed Sep 11 2013 15:32:25 GMT+0800 (中国标准时间)
[ { Variable_name: 'wait_timeout', Value: '10' } ]
Wed Sep 11 2013 15:32:30 GMT+0800 (中国标准时间)
[ { Variable_name: 'wait_timeout', Value: '10' } ]
Wed Sep 11 2013 15:32:35 GMT+0800 (中国标准时间)
[ { Variable_name: 'wait_timeout', Value: '10' } ]
连接池,已经解决了自动重连的问题了,后面我们的开发,可以尽量使用pooling的方式。
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