Spring

spring.datasource.url=jdbc:mysql://localhost:yourDatabase?serverTimezone=UTC spring.datasource.username=${USERNAME} spring.datasource.password=${PASSWORD} spring.jpa.hibernate.ddl-auto=create-drop spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect spring.logging.level.org.hibernate.SQL=debug spring.jpa.show-sql=truespring.datasource.url=jdbc:mysql://localhost:yourDatabase?serverTimezone=UTC spring.datasource.username=${USERNAME} spring.datasource.password=${PASSWORD} spring.jpa.hibernate.ddl-auto=create-drop spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect spring.logging.level.org.hibernate.SQL=debug spring.jpa.show-sql=true

RowMapper interface: RowMapper is a callback interface used by JdbcTemplate’s query methods to process the ResultSet. It actually maps each row of ResultSet to a user defined object. Method of ResultSetExtractor interface: public T query(String sql,RowMapper<T> rm) Where T represents the return type. Example package com.w3spoint.SpringDB;   import java.util.List;   import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.ApplicationContext;   @SpringBootApplication public … Read more

ResultSetExtractor interface: ResultSetExtractor is a callback interface used by JdbcTemplate’s query methods to process the ResultSet. It extract or fetch results from a ResultSet. However RowMapper is a better choice for processing the ResultSet. Method of ResultSetExtractor interface: public T extractData(ResultSet rs)throws SQLException,DataAccessException Where T represents the return type. Example package com.w3spoint.SpringDB;   import java.util.List;   import org.springframework.boot.SpringApplication; import … Read more

PreparedStatementCallback interface: The PreparedStatementCallback is a generic callback interface for code that operates on a PreparedStatement. Allows to execute any number of operations on a single PreparedStatement i.e. a single executeUpdate call or repeated executeUpdate calls with varying parameters. We pass the PreparedStatementCallback’s instance in the execute method for executing parameterized queries. Syntax: public T execute(String sql,PreparedStatementCallback<T>); Where … Read more

Problems with JDBC API: We have to write unnecessary code for creating database connections, SQL statement executions, exception handling, transaction handling and closing database connections etc. Spring JDBC Framework: In case of Spring JDBC Framework it takes care of all things like creating database connections, executing SQL statements, handling exceptions, handling transactions and closing database … Read more

Spring bean autowire by constructor is analogous to spring bean autowire by type but applies to constructor arguments. Let’s discuss spring bean autowire by constructor with below example. In below example we have SortNumbers class which have one dependency for sorting implementation. We use spring bean autowire by constructor here as we take sortAlgo as … Read more

Allows a property to be autowired if there is exactly one bean of the property type in the application context. If there is more than one, a fatal exception is thrown. Let’s discuss spring bean autowire by type with below example. In below example we have SortNumbers class which have one dependency for sorting implementation. … Read more

Autowiring by property name. This will inspect the application context and look for a bean named exactly the same as the property which needs to be autowired. Let’s discuss spring bean autowire by name with below example. In below example we have SortNumbers class which have one dependency for sorting implementation. We use spring bean … Read more

Autowiring is the process of placing an instance of one bean into the specified field in an instance of another bean.   How Spring Autowiring Works? All spring beans are managed by spring container called “application context”. The autowiring happens at the time of application starts up. When any autowiring configuration is found either by xml … Read more

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