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Configurations
All functions of jSqlBox are based on DbContext. DbContext is a sessionless lightweight object. The easiest way to use it is to create an instance with the new DbContext () or new DbContext (DataSource) method, so that for novices Get started soon, but for situations where you need to change the default configuration and provide more features (such as transaction management, log output, etc.), more configuration is necessary. There are two ways to configure DbContext:
Examples of use are as follows:
DbContextctx = new DbContext (ds);
ctx.setDialect (Dialect.H2); // Set dialect
ctx.setAllowShowSQL (true); // Allow log output
DbContext is a pseudo-thread-safe object. All the methods that start with set are not thread-safe, but as long as these set methods are guaranteed to be called only once when the program starts, it will not affect the thread safety of the DbContext instance. All configuration methods are as follows:
setAllowShowSQL (Boolean) // Enable or disable log output function, see below
setBatchSize (Integer) // Set the default number of batch cache, see below
setConnectionManager (ConnectionManager) // Set the connection manager, see "Transaction Configuration"
setMasters (DbPro []) // Set a group of master libraries
setMasterSlaveOption (SqlOption) // Set the master-slave library access strategy, see "Sub-library sub-table"
setName (String) // Set a name for itself
setSlaves (DbPro []) // Set a group of slave DbContext
setSqlHandlers (SqlHandler []) // Set a set of global interceptors, see "Introduction to Handler class"
setSqlTemplateEngine (SqlTemplateEngine) // Set template engine, see "tXxxx template method"
setDialect (Dialect) // Manually specify the database dialect of DbContext, instead of the jSqlBox automatically guessing the dialect type based on the DataSource
setShardingTools (ShardingTool []) // Set a Sharding tool, see "Sharding" chapter
setSnowflakeCreator (SnowflakeCreator) // Set a distributed primary key generator, see "Sharding"
setGlobalNextAuditorGetter (Object) // See @CreateBy and @LastModifiedBy section of entity annotation
setIgnoreNull (boolean) // Default is false, if set to true, all entities will ignore the field with a value of null when saving or updating, use with caution!
setIgnoreEmpty (boolean) // The default is false. If set to true, all entities will ignore fields with null or empty string when saving or updating. Use with caution!
The setIgnoreNull and setIgnoreEmpty methods should be used with caution, because it ignores null or empty attributes when the entity is stored or updated. Generally do not open these two switches, but manually add an IGNORE_NULL or IGNORE_EMPTY parameter when the entity is inserted or updated, such as: user.insert (DB.IGNORE_EMPTY); Although this is a little more troublesome, it can better control the handling of null and null values of entity fields.
Calling the following static methods in DbContext can also achieve the purpose of rapid configuration:
setGlobalNextAllowShowSql (Boolean)
setGlobalNextBatchSize (Integer)
setGlobalNextConnectionManager (ConnectionManager)
setGlobalNextIocTool (IocTool)
setGlobalNextMasterSlaveOption (SqlOption)
setGlobalNextSqlHandlers (SqlHandler ...)
setGlobalNextTemplateEngine (SqlTemplateEngine)
setGlobalNextDialect (Dialect)
setGlobalNextShardingTools (ShardingTool [])
setGlobalNextSnowflakeCreator (SnowflakeCreator)
setGlobalNextSqlMapperGuesser (SqlMapperGuesser)
setGlobalNextAuditorGetter (Object)
setGlobalNextIgnoreEmpty (boolean)
setGlobalNextIgnoreNull (boolean)
These methods tell DbContext what the default global configuration parameters are. All methods start with "setGlobalNext", indicating that it is a global switch method, which will affect the default configuration of the next DbContext of the entire project, so use caution, usually only run once at the beginning of the program, set each The default parameters. Note that it only affects the next DbContext instance creation. For example, calling DbContext.setGlobalNextAllowShowSql (true) when the DbContext has been created will not affect the previously created DbContext instance.
In the jSqlBox, except for the logging system, all configuration is done through Java code. For the configuration that must be changed by reading the configuration file, please implement the conversion of the configuration file to Java configuration.
DbContext.setGlobalDbContext (DbContext); It means to set the default global DbContext instance of the entire project. It is usually used for ActiveRecord instances in the case of a single data source, for example: new User (). insert (); In this usage, if the User instance does not configure its own DbContext (see the "ActiveRecord" section for details), it will call this default global DbContext instance for database access operations. In the program, you can use the static method DbContext.getGlobalDbContext () or DB.gctx () method to get this default global DbContext instance.
This setting is used to set whether to allow jSqlBox to output logs, and the default is off. Turn on this switch, you should be able to see the log output to the console, but it is not necessarily related to what log tool jSqlBox is configured and the settings of the log tool itself configuration file, for example, in the root directory of the project (corresponding to the main development environment / resources directory) Add a text file "jlogs.properties" with the following content: log = com.github.drinkjava2.jlogs.SimpleSLF4JLog Then the whole project will use SLF4J for log output.
There is a batch switch function in jSqlBox. SQL batch insert and update statements are cached in memory, and then the batch function of the database (if supported) is refreshed to the database once to speed up. The setBatchSize method is used to set the cache size , The default value is 300. (See "Batch Processing" section for details)
This is related to transactions, please refer to the "Transaction Configuration" section for details
It is used to set one or more interceptors for the current DbContext. All pintea SQL operations based on this DbContext instance are processed by the interceptor. For details, see "Handler Class Introduction".
jSqlBox comes with a simple template engine, but it can use the setSqlTemplateEngine method to switch the template engine configuration, which has been introduced in the "t series template method" section. Note that the template engine can not only be set in DbContext, but also can be used as a method parameter in the pintea system for temporary use.
There is an example in the demo / jsqlbox-beetl directory of jSqlBox, which demonstrates how to customize your own SQL template in jSqlBox. This example uses Beetl as the template engine
Specify the database dialect of the DbContext instance instead of guessing the dialect type based on the DataSource. If you do not specify a dialect when constructing the DbContext instance, it will obtain a connection from the DataSource, read the database's MetaData, and automatically guess the current database dialect type. (See jDialects project for details).
Set the name of the current DbContext instance. In some occasions (such as in a library and table environment), you can use this name to distinguish different context instances.
The following is the configuration related to the sub-library sub-table, see the section “Sub-library sub-table” for details
setMasterSlaveOption (SqlOption) Set master-slave library access strategy setMasters (DbPro []) Set a set of master libraries setSlaves (DbPro []) Set a set of slave libraries setShardingTools (ShardingTool []) Set a Sharding tool setSnowflakeCreator (SnowflakeCreator) sets a distributed primary key generator instance