Spring Boot: Comment externaliser la configuration de la source de données JDBC?

Question

J'ai le code de contrôleur Spring Boot suivant qui fonctionne. (Un texte sensible a été remplacé)

package com.sample.server;

import Java.sql.ResultSet;
import Java.sql.SQLException;
import Java.util.List;

import org.Apache.commons.dbcp.BasicDataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;

@RestController
public class DetailReportController
{
    @RequestMapping(value="/report/detail", method=RequestMethod.GET)
    public List<UFGroup> detailReport()
    {
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName("net.sourceforge.jtds.jdbc.Driver");
        dataSource.setUrl("jdbc:jtds:sqlserver://111.11.11.11/DataBaseName;user=sa;password=password");

        JdbcTemplate jt = new JdbcTemplate(dataSource);

        List<UFGroup> results = jt.query(
            "select NID, SCode, SName from UFGroup",
            new RowMapper<UFGroup>()
            {
                @Override
                public UFGroup mapRow(ResultSet rs, int rowNum) throws SQLException
                {
                    return new UFGroup(rs.getInt("NID"), rs.getString("SCode"),
                            rs.getString("SName"));
                }
            });

        return results;
    }

    private static class UFGroup
    {
        public int nid;
        public String scode;
        public String sname;

        public UFGroup(int nid, String scode, String sname)
        {
            this.nid = nid;
            this.scode = scode;
            this.sname = sname;
        }
    }
}

Maintenant, je veux externaliser la configuration de la source de données . Autrement dit, la classe BasicDataSource, le nom de la classe du pilote, l’URL de la source de données doivent être placés dans application.properties . Comment puis-je procéder?

BTW, je suis un débutant de Spring, Spring Boot et même Java Beans. Tout ce que j'ai, c'est une expérience de programmation Java, principalement pour les appareils mobiles. J'ai passé quelques jours à étudier l'environnement Spring Boot, mais j'ai été littéralement submergé ... donc je vous prie de me donner les instructions exactes avec un exemple concret.

UPDATE: Lorsque j'ai appliqué la réponse de M. Deinum, l'erreur suivante s'est produite lors de l'exécution de l'application:

2013-11-18 19:37:54.789  INFO 6868 --- [           main] com.logicplant.uflow.server.Application  : Starting Application on zeo-PC with PID 6868 (C:\Projects\uFlow\Dev\Server\Spring\uFlowServer\build\libs\uFlowServer-1.0.0.jar started by zeo)
2013-11-18 19:37:54.830  INFO 6868 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@7f83698f: startup date [Mon Nov 18 19:37:54 KST 2013]; root of context hierarchy
2013-11-18 19:37:55.931  INFO 6868 --- [           main] o.Apache.catalina.core.StandardService   : Starting service Tomcat
2013-11-18 19:37:55.932  INFO 6868 --- [           main] org.Apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/7.0.42
2013-11-18 19:37:56.009  INFO 6868 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2013-11-18 19:37:56.010  INFO 6868 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1183 ms
2013-11-18 19:37:56.165  INFO 6868 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2013-11-18 19:37:56.165  INFO 6868 --- [ost-startStop-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2013-11-18 19:37:56.242  INFO 6868 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2013-11-18 19:37:56.388  INFO 6868 --- [ost-startStop-1] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/report/detail],methods=[GET],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public Java.util.List<com.logicplant.uflow.server.DetailReportController$UFGroup> com.logicplant.uflow.server.DetailReportController.detailReport()
2013-11-18 19:37:56.438  INFO 6868 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2013-11-18 19:37:56.439  INFO 6868 --- [ost-startStop-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2013-11-18 19:37:56.788  INFO 6868 --- [ost-startStop-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 622 ms
2013-11-18 19:37:56.881  INFO 6868 --- [           main] o.Apache.catalina.core.StandardService   : Stopping service Tomcat
Java.lang.reflect.InvocationTargetException
    at Sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at Sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at Sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at Java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.Java:53)
    at Java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'detailReportController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.jdbc.core.JdbcTemplate com.logicplant.uflow.server.DetailReportController.jt; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.jdbc.core.JdbcTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.Java:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.Java:1139)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.Java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.Java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.Java:299)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.Java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.Java:295)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.Java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.Java:665)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.Java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.Java:482)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.Java:122)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.Java:509)
    at org.springframework.boot.SpringApplication.run(SpringApplication.Java:278)
    at com.logicplant.uflow.server.Application.main(Application.Java:17)
    ... 6 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.jdbc.core.JdbcTemplate com.logicplant.uflow.server.DetailReportController.jt; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.jdbc.core.JdbcTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.Java:505)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.Java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.Java:289)
    ... 20 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.jdbc.core.JdbcTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.Java:1051)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.Java:919)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.Java:820)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.Java:477)
    ... 22 more

Pour référence, le contenu du fichier build.grade (j'utilise Gradle) est le suivant: (suivant la suggestion de M. Deinum, j'ai supprimé la dépendance pour org.Apache.commons.dbcp.)

buildscript {
    repositories {
        maven { url "http://repo.spring.io/libs-snapshot" }
        mavenLocal()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:0.5.0.M5")
    }
}

apply plugin: 'Java'
apply plugin: 'Eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'

jar {
    baseName = 'uFlowServer'
    version = '1.0.0'
}

repositories {
    mavenCentral()
    maven { url "http://repo.spring.io/libs-snapshot" }
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web:0.5.0.M5")
    compile("com.fasterxml.jackson.core:jackson-databind")
    compile("org.springframework:spring-jdbc:4.0.0.M3")
    runtime("net.sourceforge.jtds:jtds:1.3.1")
    testCompile("junit:junit:4.11")
}

task wrapper(type: Wrapper) {
    gradleVersion = '1.8'
}

Et ceci est le fichier Application.Java, qui est le fichier source principal.

package com.sample.server;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.SpringApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application
{
    public static void main(String args[])
    {
        SpringApplication app = new SpringApplication(Application.class);
        app.setShowBanner(false);
        app.run(args);
    }
}

Que peut-on faire pour l'erreur?

UPDATE: Comme M. Deinum l’a suggéré, lorsque j’ai modifié le fichier build.gradle comme suit, l’application a fonctionné!

buildscript {
    repositories {
        maven { url "http://repo.spring.io/libs-snapshot" }
        mavenLocal()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:0.5.0.M6")
    }
}

apply plugin: 'Java'
apply plugin: 'Eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'

jar {
    baseName = 'uFlowServer'
    version = '1.0.0'
}

repositories {
    mavenCentral()
    maven { url "http://repo.spring.io/libs-snapshot" }
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web:0.5.0.M6")
    compile("org.springframework.boot:spring-boot-starter-jdbc:0.5.0.M6")
    compile("com.fasterxml.jackson.core:jackson-databind")
    runtime("net.sourceforge.jtds:jtds:1.3.1")
    testCompile("junit:junit:4.11")
}

task wrapper(type: Wrapper) {
    gradleVersion = '1.8'
}

Answer 1

Changez votre manette comme suit

@RestController
public class DetailReportController {

    @Autowired
    private JdbcTemplate jt;

    @RequestMapping(value="/report/detail", method=RequestMethod.GET)
    public List<UFGroup> detailReport() {
        List<UFGroup> results = jt.query(
            "select NID, SCode, SName from UFGroup",
            new RowMapper<UFGroup>(){
                @Override
                public UFGroup mapRow(ResultSet rs, int rowNum) throws SQLException {
                    return new UFGroup(rs.getInt("NID"), rs.getString("SCode"), rs.getString("SName"));
                }
            });
        return results;
    }

    private static class UFGroup
    {
        public int nid;
        public String scode;
        public String sname;

        public UFGroup(int nid, String scode, String sname)
        {
            this.nid = nid;
            this.scode = scode;
            this.sname = sname;
        }
    }
}

Dans src/main/resources ajouter un application.properties avec ce qui suit

spring.datasource.driverClassName=net.sourceforge.jtds.jdbc.Driver
spring.datasource.url=jdbc:jtds:sqlserver://111.11.11.11/DataBaseName
spring.datasource.username=sa
spring.datasource.password=password

Et commencez simplement votre application. Aucun xml requis. Le démarrage de printemps créera la variable DataSource et ajoutera une instance JdbcTemplate par défaut. 

Conseil: Supprimez la dépendance pour org.Apache.commons.dbcp. Spring-boot vous donnera le pool de connexions Tomcat le plus récent (et le meilleur à mon humble avis) (qui, malgré le nom, peut être utilisé entièrement seul).

Answer 2

Je vais remodifier votre code dans une meilleure approche.

Tout d’abord, nul besoin d’utiliser un nouvel opérateur dans votre code puisque vous utilisez Spring, vous pouvez donc utiliser la puissante fonctionnalité de Spring i.e Dependency Injection.

@RestController
public class DetailReportController
{       @Required
            private JdbcTemplate jt;

            //setter for the same

            @RequestMapping(value="/report/detail", method=RequestMethod.GET)
    public List<UFGroup> detailReport()
    {

        List<UFGroup> results = jt.query(
            "select NID, SCode, SName from UFGroup",
            new RowMapper<UFGroup>()
            {
                @Override
                public UFGroup mapRow(ResultSet rs, int rowNum) throws SQLException
                {
                    return new UFGroup(rs.getInt("NID"), rs.getString("SCode"),
                            rs.getString("SName"));
                }
            });

        return results;
    }

    private static class UFGroup
    {
        public int nid;
        public String scode;
        public String sname;

        public UFGroup(int nid, String scode, String sname)
        {
            this.nid = nid;
            this.scode = scode;
            this.sname = sname;
        }
    }
}

application-context.xml

    <bean id="dataSource" class="org.Apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
        <property name="maxActive" value="100"/>
        <property name="maxIdle" value="30"/>
        <property name="maxWait" value="16000"/>
        <property name="minIdle" value="0"/>
    </bean>

   <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

    <property name="location">
        <value>database.properties</value>
    </property>
</bean>


    <bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate;">
         <property name="dataSource" ref="dataSource"/>
    </bean>

    <bean id="detailReportController" class="your class">
         <property name="jt" ref="jt"/>
    </bean>

Une autre suggestion que vous pouvez déplacer votre code lié à la base de données dans les classes DAO est très déconseillée d’avoir la même chose dans Controller.Else si vous souhaitez vous en tenir à votre approche, utilisez la classe Properties du package Java.util.

Vois ici