Tag Archives: JDBC

Batch error reporting in Java spring

1、 Questions

Error in starting batch task:

ERROR [com.alibaba.druid.pool.DruidDataSource]
 - {dataSource-1} init error java.sql.SQLException: oracle.jdbc.OracleDriver

2、 Solution

1. The reason is that I don’t have the jar package driven by JDBC, so I found a few on the Internet and asked me to download Ojdbc14 or ojdbc7. 14 is finished, but it’s useless. Ojdbc7 is the wrong version. Later, I opened the library and found that there are problems with both downloads;

You can only delete these invalid jar packages, and then find a JDBC 6 jar package to put on. The result is OK;

No matching editors or conversion strategy found

1、 Questions

Recently, I’ve been building the batch framework of spring, and frequent errors have been reported. It’s a trip to the pit;

Cannot convert value of type 'java.lang.String' to 
required type 'javax.sql.DataSource' for property 'dataSource': 
no matching editors or conversion strategy found

2、 Solution

The reason is that [ref] is wrongly written as [value] in the XML configuration of persistence layer;

Top35: pychar reports an error when connecting to MySQL server returns invalid timezone. Need to set ‘servertimezone’ property

Top35: Server returns invalid timezone. Need to set ‘ServerTimezone’ property.
Error content error cause solution

Content of the error

Error reason

Server returns invalid timezone. Need to set ‘ServerTimezone’ property.
The server returning an invalid time zone needs to set the ‘ServerTimeZone’ property.
reasons: MySQL driver jar package the default time zone was UTC
the UTC is the representative of a global standard time, but we use time is Beijing time zone that is east eight area, UTC eight hours ahead.
The solution
Joining together?ServerTimeZon =UTC

Use of HQL query.list () is a null pointer exception, but the database can find out the result

HQL uses query.List () as a null pointer exception, but the database can detect the result
Solutions:
Check that the database dialect is configured correctly in hibernate configuration
org.hibernate.dialect.OracleDialect

<property name="hibernateProperties">
	<props>
		<prop key="hibernate.dialect">org.hibernate.dialect.OracleDialect</prop>
		<prop key="hibernate.show_sql">true</prop>
		<prop key="dynamic-update">true</prop>
		<prop key="hibernate.jdbc.batch_size">0</prop>
	</props>
</property>

Give common database dialects

RDBMS

dialect

DB2

org. Hibernate. The dialect. DB2Dialect

DB2 AS/400 org.hibernate.dialect.DB2400Dialect
DB2 OS390 org.hibernate.dialect.DB2390Dialect
PostgreSQL org.hibernate.dialect.PostgreSQLDialect
MySQL org.hibernate.dialect.MySQLDialect
MySQL with InnoDB org.hibernate.dialect.MySQLInnoDBDialect
MySQL with MyISAM org.hibernate.dialect.MySQLMyISAMDialect
Oracle (any version) org.hibernate.dialect.OracleDialect
Oracle 9i/10g org.hibernate.dialect.Oracle9Dialect
Sybase org.hibernate.dialect.SybaseDialect
Sybase Anywhere org.hibernate.dialect.SybaseAnywhereDialect
Microsoft SQL Server org.hibernate.dialect.SQLServerDialect
SAP DB org.hibernate.dialect.SAPDBDialect
Informix org.hibernate.dialect.InformixDialect
HypersonicSQL org.hibernate.dialect.HSQLDialect
Ingres org.hibernate.dialect.IngresDialect
Progress org.hibernate.dialect.ProgressDialect
Mckoi SQL org.hibernate.dialect.MckoiDialect
Interbase org.hibernate.dialect.InterbaseDialect
Pointbase org.hibernate.dialect.PointbaseDialect
FrontBase org.hibernate.dialect.FrontbaseDialect
Firebird org.hibernate.dialect.FirebirdDialect

JDBC connect to Sql Server to connect to the database–The TCP/IP connection to the host localhost, port 1433 has failed

Have you ever made such a mistake?

The TCP/IP connection to the host localhost, port 1433 has failed.

com.microsoft.sqlserver.jdbc.SQLServerException: 
The TCP/IP connection to the host localhost, port 1433 has failed. Error: "Connection refused: connect. 
Verify the connection properties.
Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. 
Make sure that TCP connections to the port are not blocked by a firewall.".

Solutions:
1. Select the computer – & GT; Right click management – & GT; Computer management — & GT; Service and application
(1) first check SQL server service whether
has been enabled to — > SQL Server configuration Manager — & GT; SQL Server service, make sure local SQL Server service is enabled.

(2) then check SQL server network configuration
to — > SQL Server configuration Manager — & GT; SQL Server network configuration ensures that the Named Pipes and TCP/IP protocols are enabled.


2. If we run the program again, it may appear that the connection is still unsuccessful, so we can continue to solve the problem:
or code> SQL server network configuration
to — > SQL Server configuration Manager — & GT; SQL Server network configuration, Named Pipes and TCP/IP protocol is enabled, select TCP/IP right click – > Property – & gt; IP address, scroll down to see if IPALL in TCP port is 1433, no, then change to 1433.

finally, restart SQL Server service, then run the program again, successful, comfortable!

How to Fix Exception in thread “main“ com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications

this problem is in the database connection failure, looked up from the Internet, the solution is varied, there are configuration files, and change the code. But everyone makes the same mistake for different reasons.

will be stupid, suddenly realized that the database can not connect, either url, or a user name or password. Turning back, the real cause was found…

error code: 

String url="jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=true";
String username="root";
String password="123456";

remove (with warning) or change to false after url: 

String url="jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=false";
String username="root";
String password="123456";

is not an error, you can query out.