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First, a simple Lua script code is written to obtain the value value corresponding to the lock, check whether it is equal to requestId, and delete the lock (unlock) if it is equal;Then, pass the Lua code to jedis eval() method, and assign the parameter KEYS[1] to lockKey and ARGV[1] to requestId. The eval () method is to hand over the Lua code ...

If there is such a demand: In the first version of our application, there was no authorization function. The current requirement is to add an authorization function. In the above example, before we operate the order information (whether querying or modifying), we add a function to check whether the user is admin. One way to do this is to cre ...

After finishing these 33 questions, we don't have to worry about the written sql test any more. We don't talk much nonsense. Let's go straight to the dry goods!!! 1: Title 1. Query the Sname, Ssex, and Class columns of all records in the Student table. 2. Query all the companies of teachers, that is, the non duplicate Depart ment column. 3. ...

Writing high-quality concurrent code is a very difficult task. Since the first version, the Java language has built-in support for multithreading, which was great in those years. However, when we have a deeper understanding and more practice of concurrent programming, we have more schemes and better choices to realize concurrent programming. Th ...

Advantages of thread pool The work done by the thread pool is mainly to control the number of running threads, put tasks into the queue during processing, and then start these tasks after threads are created. If the number of threads exceeds the maximum number, the exceeded threads queue up, wait for other threads to complete execution, and ...

public class ConnectionFactory { public static Connection getConn2() throws Exception { Class.forName("com.mysql.jdbc.Driver"); return DriverManager.getConnection("x", "x", "x"); } } [](https://codechina.csdn.net/m0_60958482/java-p7)FactroyBean ------------------------------------------------------------- ...

⭐ Write in front This is the way to learn the source code of Wenwen al👍 If it helps you, give the blogger a free praise to encourage QAQ👋 Blog home page 🎉 Winwin El learning house⭐ More articles 👨‍🎓 Stay tuned to wenwendell's home page🍅 Article release date: December 2021 sixteen👋 java learning road!🔎 For more articles, pleas ...

1. What is a closure function based on JS and what is it used for? var i=10; function add1(){ alert(i); i++; } function add2(){ var j=100; alert(j); j++; } //Test: // add1(); //10 // add1(); //11 // add1(); //12 // // add2(); //10 // add2(); //10 // add2(); //10 The reason is simple i is a global variab ...

🎄 preface This article mainly summarizes the handwritten questions in 2021, which are from the front end of the year and the autumn entrance examination. The topic comes from the front end of Niu Kwai network. The statistical time is from the beginning of March to the end of October. The 15 companies came from Ali, Tencent, Baidu, bytes, USA ...

1, Tree 1. General Different from the one-to-one linear relationship represented by the linear table, the tree represents the more complex nonlinear relationship between data elements.Intuitively, the tree is a hierarchical structure defined by branch relationship, which is a one to many relationshipDefinition of tree: a tree is a finite set ...