mysql搭建Windows+Node.js+MySQL环境的教程(2)

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。

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