Programmer Group

Recently, because the project needs to do data synchronization between two projects, specifically project 1's data is synchronized to project 2 through message queue, because this update operation also involves updating the data of multiple databases, so it needs the operation of switching multiple data sources. Here's how to switch data source ...

dbcp is an open source connection pool for apache. C3P0 is an open source JDBC connection pool, which implements data source and JNDI binding, supports JDBC3 specification and JDBC2 standard extension. At present, open source projects using it include Hibernate, Spring, etc. Simple use of dbcp First, you must import the relevant jar package ...

Bullshit does not say much directly on the code "novice on the road God do not spray!" 1 First, you need to build a Springboot project. I won't show you how to build it. 2. Configure two data sources in the configuration file 3. Setting up two config classes import org.apache.ibatis.session.SqlSessionFactory ...

DBHelper class design - Connect to mysql database _DBHelper (DataBase Helper) is mainly used to help us operate the database, in which we will create a method to obtain database connections. We'll put it in the util ity package, which acts as a toolkit. In order to access MySQL database, we need a jar package to connect mysql: mysql-connecto ...

IOC of spring I. Introduction to spring The Spring framework is a layered architecture consisting of seven well-defined modules. The Spring module is built on top of the core container, which defines how bean s are created, configured, and managed. Each module (or component) that makes up the Spring framework can exist independently or b ...

What is DAO? DAO is Data Access Object Data Access Interface, as its name implies: dealing with the database. Sandwiched between business logic and data resources. What are the DAO models? The DAO pattern is actually a combination of two patterns: the Data Accessor pattern and the Active Domain Object pattern. Their significance an ...

Running batch updates on a very low-configuration machine today~~~ Running for about 30 minutes ~~This configuration ~~This program~~~ And then the magnificent newspaper went off the beaten track.~~~ This is the specific exception. DEBUG: (BaseJdbcLogger.java:132) ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@4d4 ...

Recent problems encountered in writing a small program: I use the c3p0 connection pool for database connection, the project of eclipse imported in MyEclipse 2014 environment, and configure it in the c3p0 configuration file (c3p0-config.xml) as follows: <?xml version="1.0" encoding="UTF-8"?> <c3p0-config> <default-config> ...

1.Maven refers to the jar package The default mybatis can't print out the SQL log, which is not easy to view and debug. It needs to be combined with log4jdbc-log4j2 to complete the input of the debugging information of SQL. Configure maven with pom.xml. Note that all three of the following are required <dependency>         &lt ...

The reasons for the error are as follows: Exception in thread "main" org.hibernate.exception.JDBCConnectionException: Cannot open connection at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:99) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.exception.JDBCExc ...