Polish "Allow to customize the JdbcTemplate"

Closes gh-7960

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/JdbcProperties.java

@@ -22,14 +22,12 @@ import org.springframework.boot.context.properties.ConfigurationProperties;
  * Configuration properties for JDBC.
  *
  * @author Kazuki Shimizu
- * @since 1.5.0
+ * @author Stephane Nicoll
+ * @since 2.0.0
  */
 @ConfigurationProperties(prefix = "spring.jdbc")
 public class JdbcProperties {
 
-	/**
-	 * Settings for JdbcTemplate.
-	 */
 	private final Template template = new Template();
 
 	public Template getTemplate() {
@@ -37,51 +35,51 @@ public class JdbcProperties {
 	}
 
 	/**
-	 * {@link org.springframework.jdbc.core.JdbcTemplate} settings.
+	 * {@code JdbcTemplate} settings.
 	 */
 	public static class Template {
 
 		/**
-		 * Fetch size.
-		 * @see org.springframework.jdbc.core.JdbcTemplate#fetchSize
+		 * Number of rows that should be fetched from the database when more rows are
+		 * needed. Use -1 to use the JDBC driver's default configuration.
 		 */
-		private Integer fetchSize;
+		private int fetchSize = -1;
 
 		/**
-		 * Max row count.
-		 * @see org.springframework.jdbc.core.JdbcTemplate#maxRows
+		 * Maximum number of rows. Use -1 to use the JDBC driver's default configuration.
 		 */
-		private Integer maxRows;
+		private int maxRows = -1;
 
 		/**
-		 * Query timeout in seconds.
-		 * @see org.springframework.jdbc.core.JdbcTemplate#queryTimeout
+		 * Query timeout in seconds. Use -1 to use the JDBC driver's default
+		 * configuration.
 		 */
-		private Integer queryTimeout;
+		private int queryTimeout = -1;
 
-		public Integer getFetchSize() {
+		public int getFetchSize() {
 			return this.fetchSize;
 		}
 
-		public void setFetchSize(Integer fetchSize) {
+		public void setFetchSize(int fetchSize) {
 			this.fetchSize = fetchSize;
 		}
 
-		public Integer getMaxRows() {
+		public int getMaxRows() {
 			return this.maxRows;
 		}
 
-		public void setMaxRows(Integer maxRows) {
+		public void setMaxRows(int maxRows) {
 			this.maxRows = maxRows;
 		}
 
-		public Integer getQueryTimeout() {
+		public int getQueryTimeout() {
 			return this.queryTimeout;
 		}
 
-		public void setQueryTimeout(Integer queryTimeout) {
+		public void setQueryTimeout(int queryTimeout) {
 			this.queryTimeout = queryTimeout;
 		}
+
 	}
 
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/JdbcTemplateAutoConfiguration.java

@@ -68,17 +68,10 @@ public class JdbcTemplateAutoConfiguration {
 		public JdbcTemplate jdbcTemplate() {
 			JdbcTemplate jdbcTemplate = new JdbcTemplate(this.dataSource);
 			JdbcProperties.Template template = this.properties.getTemplate();
-			if (template.getFetchSize() != null) {
-				jdbcTemplate.setFetchSize(template.getFetchSize());
-			}
-			if (template.getQueryTimeout() != null) {
-				jdbcTemplate.setQueryTimeout(template.getQueryTimeout());
-			}
-			if (template.getMaxRows() != null) {
-				jdbcTemplate.setMaxRows(template.getMaxRows());
-			}
+			jdbcTemplate.setFetchSize(template.getFetchSize());
+			jdbcTemplate.setMaxRows(template.getMaxRows());
+			jdbcTemplate.setQueryTimeout(template.getQueryTimeout());
 			return jdbcTemplate;
-
 		}
 
 	}

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -710,6 +710,11 @@ content into your application; rather pick only the properties that you need.
 	# JOOQ ({sc-spring-boot-autoconfigure}/jooq/JooqAutoConfiguration.{sc-ext}[JooqAutoConfiguration])
 	spring.jooq.sql-dialect= # Sql dialect to use, auto-detected by default.
 
+	# JDBC ({sc-spring-boot-autoconfigure}/jdbc/JdbcProperties.{sc-ext}[JdbcProperties])
+	spring.jdbc.template.fetch-size=-1 # Number of rows that should be fetched from the database when more rows are needed.
+	spring.jdbc.template.max-rows=-1 # Maximum number of rows.
+	spring.jdbc.template.query-timeout=-1 # Query timeout in seconds.
+
 	# JPA ({sc-spring-boot-autoconfigure}/orm/jpa/JpaBaseConfiguration.{sc-ext}[JpaBaseConfiguration], {sc-spring-boot-autoconfigure}/orm/jpa/HibernateJpaAutoConfiguration.{sc-ext}[HibernateJpaAutoConfiguration])
 	spring.data.jpa.repositories.enabled=true # Enable JPA repositories.
 	spring.jpa.database= # Target database to operate on, auto-detected by default. Can be alternatively set using the "databasePlatform" property.

spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -2932,11 +2932,20 @@ you can `@Autowire` them directly into your own beans:
 	}
 ----
 
+You can customize some properties of the template using the `spring.jdbc.template.*`
+properties:
+
+[source,properties,indent=0]
+----
+	spring.jdbc.template.max-rows=500
+----
+
 TIP: The `NamedParameterJdbcTemplate` reuses the same `JdbcTemplate` instance behind the
 scene. If more than one `JdbcTemplate` is defined and no primary candidate exists, the
 `NamedParameterJdbcTemplate` is not auto-configured.
 
 
+
 [[boot-features-jpa-and-spring-data]]
 === JPA and '`Spring Data`'
 The Java Persistence API is a standard technology that allows you to '`map`' objects to