node封装mysql模块

‘use strict‘<span style="color: #000000;">;
const mysql </span>= require(‘mysql‘<span style="color: #000000;">);
</span><span style="color: #0000ff;">var</span> local = <span style="color: #0000ff;">true</span>
<span style="color: #0000ff;">var</span><span style="color: #000000;"> pool
</span><span style="color: #008000;">//</span><span style="color: #008000;"> 创建连接池</span>
<span style="color: #0000ff;">if</span><span style="color: #000000;"> (local) {
    pool </span>=<span style="color: #000000;"> mysql.createPool({
        connectionLimit: </span>50<span style="color: #000000;">,
        host: </span>‘localhost‘<span style="color: #000000;">,
        user: </span>‘root‘<span style="color: #000000;">,
        password: </span>‘root‘<span style="color: #000000;">,
        database: </span>‘crawl‘<span style="color: #000000;">,
        multipleStatements: </span><span style="color: #0000ff;">true</span>  <span style="color: #008000;">//</span><span style="color: #008000;">是否允许执行多条sql语句</span>
<span style="color: #000000;">    });
} 
</span><span style="color: #008000;">//</span><span style="color: #008000;">将结果已对象数组返回</span>
<span style="color: #0000ff;">var</span> row = (sql, ...params) =><span style="color: #000000;"> {
    </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span> Promise(<span style="color: #0000ff;">function</span><span style="color: #000000;"> (resolve, reject) {
        pool.getConnection(</span><span style="color: #0000ff;">function</span><span style="color: #000000;"> (err, connection) {
            </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (err) {
                reject(err);
                </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
            }
            connection.query(sql, params, </span><span style="color: #0000ff;">function</span><span style="color: #000000;"> (error, res) {
                connection.release();
                </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (error) {
                    reject(error);
                    </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
                }
                resolve(res);
            });
        });
    });
};
</span><span style="color: #008000;">//</span><span style="color: #008000;">返回一个对象</span>
<span style="color: #0000ff;">var</span> first = (sql, ...params) =><span style="color: #000000;"> {
    </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span> Promise(<span style="color: #0000ff;">function</span><span style="color: #000000;"> (resolve, reject) {
        pool.getConnection(</span><span style="color: #0000ff;">function</span><span style="color: #000000;"> (err, connection) {
            </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (err) {
                reject(err);
                </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
            }
            connection.query(sql, params, </span><span style="color: #0000ff;">function</span><span style="color: #000000;"> (error, res) {
                connection.release();
                </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (error) {
                    reject(error);
                    </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
                }
                resolve(res[</span>0] || <span style="color: #0000ff;">null</span><span style="color: #000000;">);
            });
        });
    });
};
</span><span style="color: #008000;">//</span><span style="color: #008000;">返回单个查询结果</span>
<span style="color: #0000ff;">var</span> single = (sql, ...params) =><span style="color: #000000;"> {
    </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span> Promise(<span style="color: #0000ff;">function</span><span style="color: #000000;"> (resolve, reject) {
        pool.getConnection(</span><span style="color: #0000ff;">function</span><span style="color: #000000;"> (err, connection) {
            </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (err) {
                reject(err);
                </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
            }
            connection.query(sql, params, </span><span style="color: #0000ff;">function</span><span style="color: #000000;"> (error, res) {
                connection.release();
                </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (error) {
                    reject(error);
                    </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
                }
                </span><span style="color: #0000ff;">for</span> (let i <span style="color: #0000ff;">in</span> res[0<span style="color: #000000;">]) {
                    resolve(res[</span>0][i] || <span style="color: #0000ff;">null</span><span style="color: #000000;">);
                    </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
                }
                resolve(</span><span style="color: #0000ff;">null</span><span style="color: #000000;">);
            });
        });
    });
}
</span><span style="color: #008000;">//</span><span style="color: #008000;">执行代码，返回执行结果</span>
<span style="color: #0000ff;">var</span> execute = (sql, ...params) =><span style="color: #000000;"> {
    </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span> Promise(<span style="color: #0000ff;">function</span><span style="color: #000000;"> (resolve, reject) {
        </span><span style="color: #008000;">//</span><span style="color: #008000;"> 获取连接</span>
        pool.getConnection(<span style="color: #0000ff;">function</span><span style="color: #000000;"> (err, connection) {
            </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (err) {
                reject(err);
                </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
            }
            </span><span style="color: #008000;">//</span><span style="color: #008000;"> 操作数据库</span>
            connection.query(sql, params, <span style="color: #0000ff;">function</span><span style="color: #000000;"> (error, res) {
                </span><span style="color: #008000;">//</span><span style="color: #008000;"> 释放</span>
<span style="color: #000000;">                connection.release();
                </span><span style="color: #0000ff;">if</span><span style="color: #000000;"> (error) {
                    reject(error);
                    </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
                }
                resolve(res);
            });
        });
    });
}
</span><span style="color: #008000;">//</span><span style="color: #008000;">模块导出</span>
module.exports =<span style="color: #000000;"> {
    ROW: row,
    FIRST: first,
    SINGLE: single,
    EXECUTE: execute
}
</span><span style="color: #008000;">/*</span><span style="color: #008000;">连接mysql</span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">function</span><span style="color: #000000;"> connectToMysql() {
    </span><span style="color: #0000ff;">var</span> connection =<span style="color: #000000;"> mysql.createConnection({
        host: </span>‘‘<span style="color: #000000;">,
        user: </span>‘‘<span style="color: #000000;">,
        password: </span>‘‘<span style="color: #000000;">,
        database: </span>‘‘<span style="color: #000000;">
    });
    connection.connect();
    </span><span style="color: #008000;">//</span><span style="color: #008000;">查询</span>
    connection.query(‘SELECT * FROM user;‘, <span style="color: #0000ff;">function</span><span style="color: #000000;"> (err, rows, fields) {
        </span><span style="color: #0000ff;">if</span> (err) <span style="color: #0000ff;">throw</span><span style="color: #000000;"> err;
        console.log(</span>‘The solution is: ‘, rows[0<span style="color: #000000;">]);
    });
    </span><span style="color: #008000;">//</span><span style="color: #008000;">关闭连接</span>
<span style="color: #000000;">    connection.end();
}</span>

node封装mysql模块

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