I am trying to connect to a DM database using Spring Data JDBC and Spring Boot. I have created a simple application using Spring Tools. Spring Data JDBC does not recognize the dialect. I believe the problem is that DM is not supported DialectResolver.

@Nullable
private static Dialect getDialect(Connection connection) throws SQLException {
    DatabaseMetaData metaData = connection.getMetaData();
    String name = metaData.getDatabaseProductName().toLowerCase(Locale.ENGLISH);
    if (name.contains("hsql")) {
        return HsqlDbDialect.INSTANCE;
    } else if (name.contains("h2")) {
        return H2Dialect.INSTANCE;
    } else if (!name.contains("mysql") && !name.contains("mariadb")) {
        if (name.contains("postgresql")) {
            return PostgresDialect.INSTANCE;
        } else if (name.contains("microsoft")) {
            return SqlServerDialect.INSTANCE;
        } else if (name.contains("db2")) {
            return Db2Dialect.INSTANCE;
        } else {
            DialectResolver.LOG.info(String.format("Couldn't determine Dialect for \"%s\"", name));
            return null;
        }
    } else {
        return new MySqlDialect(getIdentifierProcessing(metaData));
    }
}

Three errors are as follows

1 Error screenshot

2 error message

[email protected]/java.lang.Thread.run(Thread.java:834)

2021-12-22 19:56:38.216 [TID: N/A] [main] INFO logger_name:o.s.b.a.l.ConditionEvaluationReportLoggingListener -

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.

2021-12-22 19:56:38.390 [TID: N/A] [main] ERROR logger_name:o.s.boot.SpringApplication - Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'jdbcConverter' defined in class path resource [org/springframework/boot/autoconfigure/data/jdbc/JdbcRepositoriesAutoConfiguration$SpringBootJdbcConfiguration.class]: Unsatisfied dependency expressed through method 'jdbcConverter' parameter 4;

nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jdbcDialect' defined in class path resource [org/springframework/boot/autoconfigure/data/jdbc/JdbcRepositoriesAutoConfiguration$SpringBootJdbcConfiguration.class]: Bean instantiation via factory method failed; nested exception is

org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.relational.core.dialect.Dialect]: Factory method 'jdbcDialect' threw exception; nested exception is org.springframework.data.jdbc.repository.config.DialectResolver$NoDialectException: Cannot determine a dialect for

org.springframework.jdbc.core.JdbcTemplate@499a93a9. Please provide a Dialect.

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jdbcDialect' defined in class path resource [org/springframework/boot/autoconfigure/data/jdbc/JdbcRepositoriesAutoConfiguration$SpringBootJdbcConfiguration.class]: Bean instantiation via factory method failed;

nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.relational.core.dialect.Dialect]: Factory method 'jdbcDialect' threw exception; nested exception is org.springframework.data.jdbc.repository.config.DialectResolver$NoDialectException: Cannot determine a dialect

for org.springframework.jdbc.core.JdbcTemplate@499a93a9. Please provide a Dialect.

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.relational.core.dialect.Dialect]: Factory method 'jdbcDialect' threw exception; nested exception is org.springframework.data.jdbc.repository.config.DialectResolver$NoDialectException: Cannot determine a dialect for

org.springframework.jdbc.core.JdbcTemplate@499a93a9. Please provide a Dialect.

at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)

at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:652)

... 34 common frames omitted

Caused by: org.springframework.data.jdbc.repository.config.DialectResolver$NoDialectException: Cannot determine a dialect for org.springframework.jdbc.core.JdbcTemplate@499a93a9. Please provide a Dialect.

The four project configurations are as follows

1 Maven dependency added

<dependency>
   <groupId>com.dameng</groupId>
   <artifactId>Dm8JdbcDriver18</artifactId>
   <version>8.1.1.49</version>
</dependency>
<dependency>
   <groupId>com.dameng</groupId>
   <artifactId>DmDialect-for-hibernate5.0</artifactId>
   <version>8.1.1.49</version>
</dependency>

Five solutions

The Spring Data JDBC library itself does not include a ready-made DM, the Firebird dialect, so you need to provide one yourself. Annotate the underlying configuration of the Spring JDBC documentation :

Dialects are resolved JdbcOperationsby JdbcDialectResolverthe pass inspection, usually by inspection . You can let Spring auto-discover the creation of pass Connectionby registering classes that implement the following . Discovery uses Spring's classpath to implement the dialect provider from within the dialect .Dialect org.springframework.data.jdbc.repository.config.DialectResolver$JdbcDialectProviderMETA-INF/spring.factoriesDialectResolverSpringFactoriesLoader

To use DM, Firebird, you need to define three things:

dialect
Dialect parser
Configuration files for Spring to find dialect resolvers

The dialect could be something like ( note that this dialect assumes DM , Firebird 3 or later ):

package spring.dm;

import org.springframework.data.relational.core.dialect.AnsiDialect;
import org.springframework.data.relational.core.dialect.ArrayColumns;
import org.springframework.data.relational.core.dialect.LockClause;
import org.springframework.data.relational.core.sql.LockOptions;

public class DMDialect extends AnsiDialect {
    public static final DMDialect INSTANCE = new DMDialect();
    @Override
    public LockClause lock() {
        return LOCK_CLAUSE;
    }

    @Override
    public ArrayColumns getArraySupport() {
        return ArrayColumns.Unsupported.INSTANCE;
    }

    private static final LockClause LOCK_CLAUSE = new LockClause() {

        @Override
        public String getLock(LockOptions lockOptions) {
            return "WITH LOCK";
        }

        @Override
        public Position getClausePosition() {
            return Position.AFTER_ORDER_BY;
        }
    };
}

Dialect resolver, returns the dialect if connected to a Firebird database .

package spring.dm;

import org.springframework.data.jdbc.repository.config.DialectResolver;
import org.springframework.data.relational.core.dialect.Dialect;
import org.springframework.jdbc.core.ConnectionCallback;
import org.springframework.jdbc.core.JdbcOperations;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.Locale;
import java.util.Optional;

public class DMDialectResolver implements DialectResolver.JdbcDialectProvider {

    @Override
    public Optional<Dialect> getDialect(JdbcOperations jdbcOperations) {
        return Optional.ofNullable(
                jdbcOperations.execute((ConnectionCallback<Dialect>)DMDialectResolver::getDialect )
        );
    }
    private static Dialect getDialect(Connection connection) throws SQLException {
        DatabaseMetaData metaData = connection.getMetaData();
        String name = metaData.getDatabaseProductName().toLowerCase( Locale.ROOT);
        if (name.contains("dm dbms")) {
            return DMDialect.INSTANCE;
        }
        return null;
    }
}

Finally, you need to define a resource named spring.factoriesMETA-INF , this file must contain the following line

org.springframework.data.jdbc.repository.config.DialectResolver$JdbcDialectProvider=spring.firebird.FirebirdDialectResolver

This allows Spring Data JDBC to discover the dialect resolver and use it

Six other questions

1. The field length of Dameng word is fixed

The field length of Dameng database will not increase automatically. For example, if the string length is 50, an error will be reported if the stored string exceeds 50, but mysql will not.

Springboot2.x+springjdbc+Dameng database

--Unable to recognize Spring Data JDBC DM dialect

a similar problem

1 Spring Data REST @Idclass not recognized

2 Spring JDBC and Firebird database

3 Spring Data JDBC/Spring Data JPA 与 Hibernate

Two problem description

Three errors are as follows

1 Error screenshot

2 error message

The four project configurations are as follows

1 Maven dependency added

Five solutions

Six other questions

1. The field length of Dameng word is fixed

references

Unrecognized Spring Data JDBC Firebird dialect - Stack Overflow

The magical effect of spring.factories - Programmer Sought

https://blog.csdn.net/mamamalululu00000000/article/details/86711079

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