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#Autowired bean is null when referenced in the constructor of another bean
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Closed 3 years ago.
I'm trying to define datasource and jdbctemplate beans inside a configuration class. How ever whenever I autowire them into Restcontroller class both of them gets null. Why?
inside my config class
#Configuration
#ComponentScan({ "org.airi.airibot.controllers", "org.airi.airibot.configs" })
public class DatabaseConfig {
#Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("org.postgresql.Driver");
dataSource.setUrl("jdbc:postgres://localhost:5432/testdb");
dataSource.setUsername("testuser");
dataSource.setPassword("testpassword");
return dataSource;
}
#Bean
public SimpleJdbcCall spCall() {
SimpleJdbcCall sp_call = new SimpleJdbcCall(dataSource());
return sp_call;
}
#Bean public JdbcTemplate jdbcTemplate() {
JdbcTemplate jdbc_template = new JdbcTemplate(dataSource());
return jdbc_template;
}
}
inside restcontroller class
#CrossOrigin(origins = "http://localhost:4200")
#RestController
public class TestController {
#Autowired
public DataSource dataSource;
#Autowired
public JdbcTemplate jdbcTemplate;
private List<DiscordServer> servers = createList();
#RequestMapping(value = "/server-emotes", method = RequestMethod.GET, produces = "application/json")
public List<DiscordServer> getServers() {
return servers;
}
private List<DiscordServer> createList() {
List<DiscordServer> temp_servers = new ArrayList<>();
//TODO: logic to add servers
System.out.println(dataSource);
return temp_servers;
}
public int getCountOfServers() {
int server_count = jdbcTemplate.queryForObject( "SELECT COUNT(*) FROM DISCORD_SERVER",Integer.class);
return server_count;
}
}
Each time I try to compile I get null pointer exception coming from the autowired fields even if I didn't instantiate anything manually and just let spring manage all instances by autowiring.
Did you try to put to constructor. And make them private. Like that
private DataSource dataSource;
private JdbcTemplate jdbcTemplate;
#Autowired
TestController (DataSource dataSource, JdbcTemplate jdbcTemplate){
this.dataSource = dataSource;
this.jdbcTemplate = jdbcTemplate;
}
Related
I am using Spring Boot for my application. I am defining JNDI name in the application.properties file.
When I am trying to get JdbcTemplate in below class, its null:
#Configuration
public class DemoClass
{
#Autowired
private JdbcTemplate template;
#Bean
private DataSource getDS(){
return template.getDataSource(); //NPE
}
}
Another Class
#Component
public class SecondClass {
#Autowired
private JdbcTemplate template;
public void show(){
template.getDataSource(): // Working Fine
}
}
I am not sure this configured by default.. In case it is not, then maybe you can try configuring it yourself:
#Autowired
DataSoure dataSource;
#Bean
public JdbcTemplate getJdbcTemplate() {
return new JdbcTemplate(dataSource);
}
in any case if you need only the DataSource, I think it is auto-configured by Spring Boot so you can autowire it directly when you need it.
#Repository
public class DataRepository {
private JdbcTemplate jdbcTemplate;
#Autowired
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
public int updateCandidate() {
return this.jdbcTemplate.update("update .... from table where ....");
}
}
application.properties
database connection details
spring.datasource.url=jdbc:oracle:thin:***
spring.datasource.username=Scott
spring.datasource.password=Tiger
spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver
spring.datasource.tomcat.initial-size=1
spring.datasource.tomcat.max-active=1
spring.datasource.tomcat.min-idle=1
spring.datasource.tomcat.max-idle=1
If you're getting a NPE at getDS. This means JdbcTemplate hasn't been injected yet, maybe it couldn't be injected.
Give spring a hint at bean dependencies by
#Bean
public JdbcTemplate getJdbcTemplate(DataSource dataSource){
return new JdbcTemplate(dataSource)
}
Or
#Bean
#DependsOn("template")
public DataSouce getDS(){
return template.getDataSource();
}
By default #Autowired sets required=true so the DemoClass should not be constructed by Spring.
Most likely you are creating new DemoClass() or disabled the annotation config altogether and the DemoClass class is registered manually e.g. using XML.
Instead ensure that the DemoClass class is discovered using Spring's component scan e.g. using #SpringBootApplication or #ComponentScan e.g. as per this example.
I have two projects one with DAO classes and Model and another with Rest Controller
Project A : DAO Classes + Model
Project B : Rest Controller
Project A
application.properties:
spring.abcDatasource.url=
spring.abcDatasource.username=
spring.abcDatasource.password=
spring.abcDatasource.driver-class-name=oracle.jdbc.driver.OracleDriver
spring.xyzDatasource.url=
spring.xyzDatasource.username=
spring.xyzDatasource.password=
spring.xyzDatasource.driver-class-name=oracle.jdbc.driver.OracleDriver
spring.datasource.initialize=false
DBConfiguration.java
#Configuration
public class DBConfiguration {
#Primary
#Bean(name = "abcDS")
#ConfigurationProperties(prefix = "spring.abcDatasource")
public DataSource abcDS() {
return DataSourceBuilder.create().build();
}
#Bean(name = "abcJdbc")
public JdbcTemplate abcJdbcTemplate(#Qualifier("abcDS") DataSource abcDS) {
return new JdbcTemplate(abcDS);
}
#Bean(name = "xyzDS")
#ConfigurationProperties(prefix = "spring.xyzDatasource")
public DataSource xyzDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "xyzJdbc")
public JdbcTemplate ebsJdbcTemplate(#Qualifier("xyzDS") DataSource xyzDatasource) {
return new JdbcTemplate(xyzDatasource);
}
}
AlphaDAO.Java
#Repository
public class AlphaDAO{
#Autowired
#Qualifier("abcJdbc")
private JdbcTemplate abcJdbc;
#Autowired
#Qualifier("xyzJdbc")
private JdbcTemplate xyzJdbc;
SqlParameterSource namedParameters;
public Collection<Alpha> findAll(String owner){
String sql = "SELECT * from alpha where OWNER in (:owner)" ;
NamedParameterJdbcTemplate namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(abcJdbc.getDataSource());
namedParameters = new MapSqlParameterSource("owner", owner);
List<Alpha> list = namedParameterJdbcTemplate.query(sql,namedParameters,
new BeanPropertyRowMapper(Alpha.class));
return list;
}
Project B Rest Controller :
AlphaServiceApplication.java
#SpringBootApplication
#EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
public class AlphaServiceApplication extends SpringBootServletInitializer implements WebApplicationInitializer {
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
return builder.sources(AlphaServiceApplication.class);
}
public static void main(String[] args) {
SpringApplication.run(AlphaServiceApplication.class, args);
}
}
AlphaServiceController.java
#RestController
public class AlphaServiceController {
private static final Logger logger = LoggerFactory.getLogger(AlphaServiceController.class);
#Autowired
AlphaDAO dao;
#CrossOrigin(origins = "http://localhost:4200")
#RequestMapping("/alpha")
public Collection<Alpha> index(#RequestBody String owner) {
return dao.findAll(owner);
}
If I try to run the rest controller I am getting the error saying
APPLICATION FAILED TO START
Description:
Field dao in com.xyz.web.wip.AlphaService.AlphaServiceController required a bean of type 'com.xyz.comp.wip.alphaComp.dao.AlphaDAO' that could not be found.
Action:
Consider defining a bean of type 'com.xyz.comp.wip.alphaComp.dao.AlphaDAO' in your configuration.
Your AlphaDao class doesnt make much sense, you are trying to autowire two fields but you still have a constructor.
Spring cant build the object because there is no qualifier on the constructor.
You can either do constructor injection or field injection but you shouldn’t use both.
I would recommend using constructor injection.
#Repository
public class AlphaDAO{
private final JdbcTemplate abcJdbc;
private final JdbcTemplate xyzJdbc;
#Autowired
public AlphaDAO(
#Qualifier("abcJdbc") JdbcTemplate abcJdbc,
#Qualifier("xyzJdbc") JdbcTemplate xyzJdbc){
this.abcJdbc = abcJdbc;
this.xyzJdbc = xyzJdbc;
}
Also remove your #Bean method from the controller.
Since the DAO classes and Rest Controller is in different packages. Added scanBasePackages to #SpringBootApplication annotation with one level up worked fine.
AlphaServiceApplication.java
#SpringBootApplication(scanBasePackages = { "com.xyz" })
In an spring boot project, is there a way to use injected object inside a #Bean method. In my example following, isdatasourceUse() method able to acccess injected Datasource (either from dev or war profile)
#EnableScheduling
#Configuration
#EnableAspectJAutoProxy
#Profile({ "dev", "war" })
public class AppConfig {
Logger logger = LoggerFactory.getLogger(AppConfig.class);
#Autowired
DBPropertyBean dbPropertyBean;
#Bean(destroyMethod = "")
#Profile("war")
public DataSource jndiDataSource() throws IllegalArgumentException, NamingException {
JndiObjectFactoryBean bean = new JndiObjectFactoryBean();
bean.setJndiName(dbPropertyBean.getJndiName());
bean.setProxyInterface(DataSource.class);
bean.setLookupOnStartup(false);
bean.afterPropertiesSet();
return (DataSource) bean.getObject();
}
#Bean(destroyMethod = "close")
#Profile("dev")
public DataSource getDataSource() throws Exception {
com.mchange.v2.c3p0.ComboPooledDataSource ds = new com.mchange.v2.c3p0.ComboPooledDataSource();
ds.setUser(dbPropertyBean.getDsUsername());
ds.setPassword(dbPropertyBean.getDsPassword());
ds.setJdbcUrl(dbPropertyBean.getDsJdbcUrl());
ds.setDriverClass(dbPropertyBean.getDsDriverClass());
ds.setMaxPoolSize(dbPropertyBean.getDsMaxPoolSize());
ds.setMinPoolSize(dbPropertyBean.getDsMinPoolSize());
ds.setInitialPoolSize(dbPropertyBean.getDsInitPoolSize());
ds.setAcquireIncrement(dbPropertyBean.getDsAcquireInc());
ds.setAcquireRetryAttempts(dbPropertyBean.getDsAcquireRetryAtt());
ds.setPreferredTestQuery(dbPropertyBean.getPreferredTestQuery());
ds.setIdleConnectionTestPeriod(dbPropertyBean.getIdleConnectionTestPeriod());
return ds;
}
#Bean
public void datasourceUse() {
//How to user datasource here
}
}
Use it like below:
#Autowired
public void datasourceUse(DataSource dataSource) {
System.out.println(dataSource);
}
I am trying to setup multiple data sources(MySql, Postgres & Oracle) using Spring boot. I am not using JPA. Setting up with a JdbcTemplate.
I have tried setting up something like this.
application.properties
spring.datasource.test-oracle.username=test-oracle
spring.datasource.test-oracle.password=test-password
spring.datasource.test-oracle.url=dburl/test
spring.datasource.test-oracle.driver-class-name=oracle.jdbc.OracleDriver
spring.datasource.int-oracle.username=int-oracle
spring.datasource.int-oracle.password=int-password
spring.datasource.int-oracle.url=dburl/int
spring.datasource.int-oracle.driver-class-name=oracle.jdbc.driver.OracleDriver
spring.datasource.d.int-mysql.username=user
spring.datasource.d.int-mysql.password=password
spring.datasource.d.int-mysql.url=dburl/d
spring.datasource.d.int-mysql.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.m.int-mysql.username=user
spring.datasource.m.int-mysql.password=password
spring.datasource.m.int-mysql.url=dburl/m
spring.datasource.m.int-mysql.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.d.test-mysql.username=user
spring.datasource.d.test-mysql.password=password
spring.datasource.d.test-mysql.url=dburl/d
spring.datasource.d.test-mysql.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.m.test-mysql.username=user
spring.datasource.m.test-mysql.password=password
spring.datasource.m.test-mysql.url=dburl/m
spring.datasource.m.test-mysql.driver-class-name=com.mysql.jdbc.Driver
MySqlConfiguration.java
#Configuration
public class MySqlConfiguration() {
#Bean(name = "dMySql")
#ConfigurationProperties(prefix = "spring.datasource.d.int-mysql")
public DataSource mysqlDrupalDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "dJdbc")
public JdbcTemplate drupalJdbcTemplate(DataSource dMySql) {
return new JdbcTemplate(dMySql);
}
#Bean(name = "mMySql")
#ConfigurationProperties(prefix = "spring.datasource.m.int-mysql")
public DataSource mysqlDrupalDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "mJdbc")
public JdbcTemplate drupalJdbcTemplate(DataSource mMySql) {
return new JdbcTemplate(mMySql);
}
}
OracleConfiguration.java
#Configuration
public class OracleConfiguration {
#Primary
#Bean(name = "tOracle")
#ConfigurationProperties(prefix = "spring.datasource.test-oracle")
public DataSource heOracleDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "tOracleJdbc")
public JdbcTemplate jdbcTemplate(DataSource tOracle) {
return new JdbcTemplate(tOracle);
}
#Bean(name = "iOracle")
#ConfigurationProperties(prefix = "spring.datasource.int-oracle")
public DataSource heOracleDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "iOracleJdbc")
public JdbcTemplate jdbcTemplate(DataSource iOracle) {
return new JdbcTemplate(iOracle);
}
}
I am not sure if the above is the correct way to go about this. When I use #Primary as per the boot docs, the Bean that has #Primary is always used. Then I use the configurations in my DAO implementations like this
One of the DAO Implementation
#Repository
public class DAOImpl implements DAOInterface {
#Autowired
#Qualifier("dJdbc")
private JdbcTemplate jdbc;
#Override
public Map<String, Object> getBasicStudentInfo(String MAIL) {
return jdbc.queryForMap(GET_BASIC_STUDENT_INFO, new Object[]{MAIL});
}
How do I go about doing this.? I did see many articles which is about mutliple datasources but unfortunately the examples or solutions don't suite me.
Further to this I need to be able to query against the DB's based on some user input. So if a user provides an environment e.g., "test" or "int", how can I trigger the correct properties based on that input.
I understand that Environment is #Autowired into Spring boot and I can intercept the user input, but unsure how I should provide the plumbing between the user input and the DAO configurations.
If something is unclear or needs a bit more explanation from my side or need more code I can provide that. Any help to resolve this situation would be appreciated.Thanks
Here is complete solution to your problem ...
Your configuration classes will look like this :
MySqlConfiguration.java
#Configuration
public class MySqlConfiguration {
#Bean(name = "dMySql")
#ConfigurationProperties(prefix = "spring.datasource.d.int-mysql")
public DataSource mysqlDrupalDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "dJdbc")
public JdbcTemplate drupalJdbcTemplate(#Qualifier("dMySql") DataSource dMySql) {
return new JdbcTemplate(dMySql);
}
#Bean(name = "mMySql")
#ConfigurationProperties(prefix = "spring.datasource.m.int-mysql")
public DataSource mysqlDrupalDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "mJdbc")
public JdbcTemplate drupalJdbcTemplate(#Qualifier("mMySql") DataSource mMySql) {
return new JdbcTemplate(mMySql);
}
}
OracleConfiguration.java
#Configuration
public class OracleConfiguration {
#Primary
#Bean(name = "tOracle")
#ConfigurationProperties(prefix = "spring.datasource.test-oracle")
public DataSource heOracleDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "tOracleJdbc")
public JdbcTemplate jdbcTemplate(#Qualifier("tOracle") DataSource tOracle) {
return new JdbcTemplate(tOracle);
}
#Bean(name = "iOracle")
#ConfigurationProperties(prefix = "spring.datasource.int-oracle")
public DataSource heOracleDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "iOracleJdbc")
public JdbcTemplate jdbcTemplate(#Qualifier("iOracle") DataSource iOracle) {
return new JdbcTemplate(iOracle);
}
}
and in your DAO class , you can autowire the JdbcTemplate like this :
#Repository
public class DAOImpl implements DAOInterface {
#Autowired
#Qualifier("dJdbc")
private JdbcTemplate dJdbc;
#Autowired
#Qualifier("mJdbc")
private JdbcTemplate mJdbc;
#Autowired
#Qualifier("tOracleJdbc")
private JdbcTemplate tOracleJdbc;
#Autowired
#Qualifier("iOracleJdbc")
private JdbcTemplate iOracleJdbc;
#Override
public Map<String, Object> getBasicStudentInfo(String MAIL) {
return dJdbc.queryForMap(GET_BASIC_STUDENT_INFO, new Object[]{MAIL});
}
.
.
.
}
Note: Make Sure to annotate one of DataSource with #Primary annotation
My setup: spring-boot version 1.2.5.RELEASE
I succeeded in running a setup like this, with the jdbc being created with the correct DataSources by adding a #Qualifier in each JDBC method creation
So, for every JDBC method you should match the qualifying datasource like this
#Bean(name = "dJdbc")
public JdbcTemplate drupalJdbcTemplate(#Qualifier("dMySql") DataSource dMySql) {
return new JdbcTemplate(dMySql);
}
No matter you choose for #Primary, using the #Qualifier for every JDBC should work good.
Autowiring jdbcTemplates in repositories, and using #Qualifier for them is ok also.
In your DAO you could wire in additional jdbctemplates. Then at runtime you can pick which one to use.
#Repository
public class DAOImpl implements DAOInterface {
#Autowired
#Qualifier("tOracle")
private JdbcTemplate testJdbc;
#Autowired
#Qualifier("intOracle")
private JdbcTemplate intJdbc;
#Override
public Map<String, Object> getBasicStudentInfo(String MAIL, String source) {
if ("TEST".equals(source)){
return testJdbc.queryForMap(GET_BASIC_STUDENT_INFO, new Object[]{MAIL});
}else {
return intJdbc.queryForMap(GET_BASIC_STUDENT_INFO, new Object[]{MAIL});
}
}
I would like to inject a specific JdbcTemplatein a Spring Boot project. I tried to follow this example for multiple DataSourceconfiguration : http://spring.io/blog/2014/05/27/spring-boot-1-1-0-m2-available-now
My code does compile and run, but only the DataSource with the #Primaryannotation is taken into account, no matter what I put as #Qualifier in the SqlServiceclass. My relevant code is the following :
DatabaseConfig.java:
#Configuration
public class DatabaseConfig {
#Bean(name = "dsSlave")
#ConfigurationProperties(prefix="spring.mysql_slave")
public DataSource slaveDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "dsMaster")
#Primary
#ConfigurationProperties(prefix="spring.mysql_master")
public DataSource masterDataSource() {
return DataSourceBuilder.create().build();
}
#Bean(name = "jdbcSlave")
#Autowired
#Qualifier("dsSlave")
public JdbcTemplate slaveJdbcTemplate(DataSource dsSlave) {
return new JdbcTemplate(dsSlave);
}
#Bean(name = "jdbcMaster")
#Autowired
#Qualifier("dsMaster")
public JdbcTemplate masterJdbcTemplate(DataSource dsMaster) {
return new JdbcTemplate(dsMaster);
}
}
And I did a quick service to try it out :
SqlService.java:
#Component
public class SqlService {
#Autowired
#Qualifier("jdbcSlave")
private JdbcTemplate jdbcTemplate;
public String getHelloMessage() {
String host = jdbcTemplate.queryForObject("select ##hostname;", String.class);
System.out.println(host);
return "Hello";
}
}
It should looks like this:
#Bean(name = "jdbcSlave")
#Autowired
public JdbcTemplate slaveJdbcTemplate(#Qualifier("dsSlave") DataSource dsSlave) {
return new JdbcTemplate(dsSlave);
}
Try to move #Qualifier annotation to the parameter on your #Bean methods for JdbcTemplate.
I guess, when you remove #Primary you end up with error, where more than one appropriate beans are presented