Introduce mybatis-plus to report an Invalid bound statement error. Move your finger to change one place

error Mybatis-Plus (MP) is an enhancement tool for mybatis. On the basis of mybatis, only enhancements are made without changes, which simplifies the development efficiency.This is to help us encapsulate some simple curd methods that can be called directly without rewriting these simple sql statements, just like JPA. A new project was created t ...

Added by zenix on Thu, 28 May 2020 06:02:40 +0300

Java creates multi-level grouping, collapses or expands grouping in Excel

This paper introduces the method of creating grouping in Excel by Java program, which can group rows or columns and set whether to expand or collapse detailed data. When you set up data groups and expand or collapse them, you can do the following:Method 1:Method of adoption sheet.groupByRows(int firstRow, int lastRow, boolean isCollapsed) shee ...

Added by sportryd on Wed, 27 May 2020 17:32:25 +0300

Consumption mode of consumer of pulsar

client processing logic ConnectionPool netty related configurations are available in com.yahoo.pulsar.client.impl.ConnectionPool public ConnectionPool(final PulsarClientImpl client, EventLoopGroup eventLoopGroup) { this.eventLoopGroup = eventLoopGroup; this.maxConnectionsPerHosts = client.getConfiguration().getConnection ...

Added by Nothsa on Wed, 27 May 2020 14:04:46 +0300

Learning C + + DLL injection and interprocess communication

I always think that learning c + + is too complex, and there are many types in it, which are too many to distinguish at all. However, most of the online materials are c + +, and some problems are not solved perfectly with other methods (can be used in c, java, python) Then I decided to do it. Because I had to do c + +, I had to do VC + +, and ...

Added by Virii on Wed, 27 May 2020 07:19:14 +0300

Java Concurrent dry goods: let you understand the producer consumer problem

Source network, only for learning, if there is infringement, please contact delete. Producer consumer model is a very classic model of multithreading concurrent cooperation. Understanding the producer consumer problem can deepen our understanding of concurrent programming. The so-called producer consumer problem, in fact, mainly contains two ...

Added by duall on Tue, 26 May 2020 13:41:25 +0300

JAVAWEB Day 6 sax parsing xml

1. Parse xml using sax - sax mode can not add or delete, only query operation Print out the entire document and execute the parse method. The first parameter is the path to the xml, and the second parameter is the parser.With respect to parsers, you need to create a class, inherit the event resolution class, and override the methods in it. ...

Added by neogranas on Mon, 25 May 2020 19:59:42 +0300

Spring MVC + POI export web data to Excel

Spring MVC + POI export web data to Excel Apache POI is an open source library of the Apache Software Foundation. POI provides the functions of reading and writing Microsoft Office files to Java programs. Next, I will release an example of Excel export based on spring MVC + Maven + poi. Welcome to criticize and correc ...

Added by Optimo on Sat, 23 May 2020 17:49:36 +0300

Configuring Maven skills in Eclipse

Configuring Maven in Eclipse Specify the path to configure and install maven Mavan local warehouse with Eclipse: Instead of the warehouse and setting we configured, you can also use the default one relation setting.xml file to configure setting.xml , plus Alibaba proxy imageIt will be slow to download jar directly from the address of the centr ...

Added by Who on Fri, 22 May 2020 19:12:18 +0300

Brief introduction of equals method of object class & String class rewrites equals method

The source code of equals method in the object class is as follows 1 public boolean equals(Object obj) 2 { 3 return this == obj; 4 } The equals method in Object directly determines whether the values of this and obj are equal. That is to say, it is used to determine whether the Object calling equals and the Object referenced by ...

Added by ben.hornshaw on Fri, 22 May 2020 18:33:03 +0300

RedisTemplate implements message queuing and inserts data in batches.

In the early stage, due to the small business volume of the production environment. So logs are commit ted one by one. There was no problem with the operation. Later, with the expansion of business concurrency, the log writing frequently deals with the database, resulting in the database connection pool often occupied, until the program crashes ...

Added by blyz on Fri, 22 May 2020 09:40:09 +0300