spring boot autowired service getting null

Question

我使用spring boot来开发web服务，在我创建一个服务和dao来访问数据库中的常量之前，一切都很正常。当我访问调用constantsService服务的方法时，它会抛出java.lang.NullPointerException错误

class constants:

public class Constantes {

public static final String AMBIENTE_EN_USO = "desarrollo";
}

接口ConstantesDAO:

public interface ConstantesDAO {

public String getMetadataInUse();
public String getIdAppLdap(String currentSchema);
public String getConstanteByNameAndSchema(String currentSchema, String constanteName);
}

类ConstantesDAOImpl

@Transactional
@Repository
public class ConstantesDAOImpl implements ConstantesDAO{

@Autowired
@Qualifier("jdbcTemplateOracle")
private JdbcTemplate jdbcTemplate2;
@Override
public String getMetadataInUse() {
String metadataInUse = null;
String SQL = "SELECT METADATA_IN_USE FROM METADATA_IN_USE_VENTAS miuv  ";
metadataInUse = jdbcTemplate2.queryForObject(SQL, String.class);

return metadataInUse;
}
@Override
public String getIdAppLdap(String currentSchema) {
String idAppLdap = null;
String SQL = "SELECT id_app_ldap FROM METADATA_VENTAS mv WHERE ID_METADATA = ? ";
idAppLdap = jdbcTemplate2.queryForObject(SQL, new Object[] { currentSchema }, String.class);

return idAppLdap;
}

@Override
public String getConstanteByNameAndSchema(String currentSchema, String constanteName) {
String constante = null;
String SQL = "SELECT " + constanteName + " FROM METADATA_VENTAS mv WHERE ID_METADATA = ? ";
constante = jdbcTemplate2.queryForObject(SQL, new Object[] { currentSchema }, String.class);

return constante;
}
}

接口ConstantesService

public interface ConstantesService {

public String getMetadataInUse();
public String getIdAppLdap(String currentSchema);
public String getConstanteByNameAndSchema(String currentSchema, String constanteName);
}

类ConstantesServiceImpl

@Service
public class ConstantesServiceImpl implements ConstantesService{

@Autowired
ConstantesDAOImpl constantesDAO;
@Override
public String getMetadataInUse() {      
//      return constantesDAO.getMetadataInUse();  //para hacerlo dimamico con la bd
return Constantes.AMBIENTE_EN_USO;
}
@Override
public String getIdAppLdap(String currentSchema) {
return constantesDAO.getIdAppLdap(currentSchema);
}

@Override
public String getConstanteByNameAndSchema(String currentSchema, String constanteName) {
return constantesDAO.getConstanteByNameAndSchema(currentSchema, constanteName);
}
}

这是呼叫

public class ManejadorArchivos {
@Autowired
private ConstantesServiceImpl constantesService;
public String[] makeFileTxt(){
try(){
String currentPath = constantesService.getConstanteByNameAndSchema(constantesService.getMetadataInUse(), "db_var");

}
rest of code....
}

}

，这是堆栈错误:

2021-02-17 13:41:44.763 ERROR 26540 --- [nio-8086-exec-1] o.a.c.c.C.[.[.[.[dispatcherServlet]      : Servlet.service() for servlet [dispatcherServlet] in context with path [/detalladoVentasWS] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
at mx.com.telcel.util.ManejadorArchivos.makeFileTxt(ManejadorArchivos.java:36) ~[classes/:na]
at mx.com.telcel.controller.RestWebController.makeFileWS(RestWebController.java:105) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:118) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:158) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:204) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:92) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:77) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.3.3.RELEASE.jar:5.3.3.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1579) [tomcat-embed-core-9.0.27.jar:9.0.27]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.27.jar:9.0.27]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_241]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_241]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.27.jar:9.0.27]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_241]

值得一提的是，我有两个连接到不同的数据库，这里的实现:

@Configuration
public class DBConfiguration {

@Bean(name = "db1")
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource dataSource1() {
return DataSourceBuilder.create().build();
}
@Bean(name = "jdbcTemplateDenodo")
public JdbcTemplate jdbcTemplateDenodo(@Qualifier("db1") DataSource ds) {
return new JdbcTemplate(ds);
}

@Bean(name = "db2")
@ConfigurationProperties(prefix = "spring.second-db")
public DataSource dataSource2() {
return  DataSourceBuilder.create().build();
}
@Bean(name = "jdbcTemplateOracle")
public JdbcTemplate jdbcTemplateOracle(@Qualifier("db2") DataSource ds) {
return new JdbcTemplate(ds);
}
}

下面是我的应用程序属性:

server.port=8086
server.servlet.context-path=/detalladoVentasWS
#denodo custom jdbc
spring.datasource.driverClassName=com.denodo.vdp.jdbc.Driver
spring.datasource.jdbcUrl=jdbc:vdb://0.0.0.0:0000/bd
spring.datasource.username=user
spring.datasource.password=pass
#second dbspring.second-db.jdbcUrl=jdbc:oracle:thin:@//0.0.0.0:0000/bd
spring.second-db.username=user
spring.second-db.password=pass
spring.second-db.driverClassName=oracle.jdbc.driver.OracleDriver

Answer 1

我将回答我自己的问题，以防有人觉得有帮助:

我是从控制器实例化ManejadorArchivos类的对象，但我是用经典的java方式通过创建原始对象的副本来实现的:

ManejadorArchivos ma =  new ManejadorArchivos();

这就是为什么spring不能识别它试图使用的常量服务。
所以答案是通过用@Service标记ManejadorArchivos类将其转换为服务。在调用它的方法时，不是在java中创建对象的副本，而是通过@Autowired:

连接它。

@RestController
public class RestWebController {
@Autowired
private ManejadorArchivosServiceImpl manejadorArchivos;
public String[] method(){
String[] res = manejadorArchivos.makeFileTxt();
return res;
}
}