When using MySQL + ibatis for insertion test, an error is reported: the information is as follows:

com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred in com/study/ibatis/Student.xml.  
--- The error occurred while applying a parameter map.  
--- Check the addStudent-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 'PRIMARY'
    at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeUpdate(MappedStatement.java:107)
    at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.insert(SqlMapExecutorDelegate.java:393)
    at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.insert(SqlMapSessionImpl.java:82)
    at com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.insert(SqlMapClientImpl.java:58)
    at com.study.ibatis.StudentDaoImpl.addStudent(StudentDaoImpl.java:33)
    at com.study.ibatis.TestIbatis.main(TestIbatis.java:14)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 'PRIMARY'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.Util.getInstance(Util.java:381)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
    at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:995)
    at com.ibatis.sqlmap.engine.execution.SqlExecutor.executeUpdate(SqlExecutor.java:80)
    at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.sqlExecuteUpdate(MappedStatement.java:216)
    at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeUpdate(MappedStatement.java:94)
    ... 5 more
false

The meaning of the error is: repeatedly enter the “1” key as “main” to enter the database and query the table TBL_When I was a student, I found three records, one of which has a primary key of 1. Considering that when I test, the default primary key in the database is 1. Therefore, delete the record with primary key 1 in the database. Then the test passed

Summary: I set the primary key in ibatis to the default 1. As a result, the test starts directly from the default 1. Then the problem is solved by reporting an error and setting the default value of the primary key to null