依赖模块：
1. mysql：/felixge/node-mysql
npm install mysql --save
2. async：/caolan/async
npm install async --save
(ps: async模块可换成其它Promise模块如bluebird、q等)
因为Node.js的mysql模块本身对于事务的封装过于简单，而且直接使用会有很严重callback hell，故我们封装了两个方法，一个用来初始化sql & params，一个用来执行事务。
初始化sql & params：
function _getNewSqlParamEntity(sql, params, callback) {if (callback) {return callback(null, {sql: sql,params: params});}return {sql: sql,params: params};}
如果你要执行多条sql语句，则需要：
var sqlParamsEntity = [];var sql1 = "insert table set a=?, b=? where 1=1";var param1 = {a:1, b:2};sqlParamsEntity.push(_getNewSqlParamEntity(sql1, param1));var sql2 = "update ...";sqlParamsEntity.push(_getNewSqlParamEntity(sql1, []));//...更多要事务执行的sql
然后我在我自己的dbHelper.js里封装了execTrans的函数，用来执行事务
var mysql = require('mysql');var async = require("async");module.exports = {execTrans: execTrans,}var pool = mysql.createPool({host: "mysql host",user: "mysql login user",password: "mysql login pwd",database: "target db name",connectionLimit: 10,port: "mysql db port",waitForConnections: false});function execTrans(sqlparamsEntities, callback) {pool.getConnection(function (err, connection) {if (err) {return callback(err, null);}connection.beginTransaction(function (err) {if (err) {return callback(err, null);}console.log("开始执行transaction，共执行" + sqlparamsEntities.length + "条数据");var funcAry = [];sqlparamsEntities.forEach(function (sql_param) {var temp = function (cb) {var sql = sql_param.sql;var param = sql_param.params;connection.query(sql, param, function (tErr, rows, fields) {if (tErr) {connection.rollback(function () {console.log("事务失败，" + sql_param + "，ERROR：" + tErr);throw tErr;});} else {return cb(null, 'ok');}})};funcAry.push(temp);});async.series(funcAry, function (err, result) {console.log("transaction error: " + err);if (err) {connection.rollback(function (err) {console.log("transaction error: " + err);connection.release();return callback(err, null);});} else {mit(function (err, info) {console.log("transaction info: " + JSON.stringify(info));if (err) {console.log("执行事务失败，" + err);connection.rollback(function (err) {console.log("transaction error: " + err);connection.release();return callback(err, null);});} else {connection.release();return callback(null, info);}})}})});});}
这样就可以执行事务了：
execTrans(sqlParamsEntity, function(err, info){if(err){console.error("事务执行失败");}else{console.log("done.");}})
