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When doing database synchronization, an error was found. mysql reported the following error: org.springframework.dao.DuplicateKeyException: ### Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException:XXX ### The error may involve com.jd.medicine.b2c.trade.center.daoHistory.RxOrd ...

1. spring spring defines things by three APIs Transaction Definition Platform Transaction Manager manages things, submits or rolls back Transaction Status represents the state in which something is running Definition of Things Transaction Definition public interface TransactionDefinition { //Isolation level int getIsolati ...

Let's briefly talk about how to use [jt400.jar] to connect to the DB2 database on AS400. jt400.jar resource, if you have AS400 client installed, refer to IBM official website ※ http://www-01.ibm.com/support/docview.wss?uid=swg21398042 Installation directory has jt400.zip, suffix can be used. If you don't have AS400 client installed, download it ...

1. spring Integration JDBC 1.spring provides many templates to integrate Dao Technology 　　 2.spring provides an object that can operate database. Objects encapsulate jdbc technology. JDBCTemplate => JDBC template object It is very similar to Query Runner in DBUtils. //0 Prepare connection pool ComboPooledDataSource dataSou ...

The first part is the reprinted article, which introduces the ways and means of transferring data from mysql to hdfs, hbase and hive. The following is an example of my own guiding mysql data to HDFS in practical projects for readers'reference. 1. Testing MySQL connections bin/sqoop list-databases --connect jdbc:mysql://192.16 ...

Label PostgreSQL , 10.0 , libpq , jdbc , failover , loadbalance , multi host , target_session_attrs background The word database should be familiar in the Internet. But how can master-backup switching and applications work together seamlessly? You may have such questions. 1. What type of QUERY is sent to the main library and what type of QUE ...

In spring mvc, the common test cases are the test service layer. Today I will show how to use spring MVC mock to test the controller layer code directly.   1. What is mock testing? mock testing is a test method that is created with a virtual object for testing some objects that are not easy to construct or acquire. 2. Why use mock t ...

When we develop enterprise applications, an operation for business people is actually a combination of multi-step operation of data reading and writing. As data operations are executed sequentially, any step of operation may be abnormal, which will lead to subsequent operations can not be completed. At this time, because the business logic is n ...

1 Discovery of problems The MySQL database, which has been good all the time, suddenly reported an error today. It was discovered by users when they queried data (web application). Take a quick look at the application log: Caused by: java.sql.SQLException: Got error 28 from storage engine at com.mysql.jdbc.SQLError.createSQLException(S ...

Some examples of the Web tier were introduced, including building RESTful API s and rendering Web views using Thymeleaf template engine, but these are not enough to build a dynamic application. Usually we do App or Web applications, we need content. Content is usually stored in various types of databases. After receiving the access request, the ...