How to resolve this org.springframework.beans.factory.UnsatisfiedDependencyException - spring-boot

Question

I am trying to using Spring boot DATA JPA to connect with the MySQL database.In that, I was trying to create a custom query but ended up with this error. Can someone help me, please?
Here is the sample code:
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'currencyExchangeController': Unsatisfied dependency expressed through field 'currencyExchage'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'currencyExchangeRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Failed to create query for method public abstract com.example.easynotes.model.CurrencyExchangeServiceBean com.example.easynotes.repository.CurrencyExchangeRepository.findByFromAndTo(java.lang.String,java.lang.String)! No property from found for type CurrencyExchangeServiceBean!
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:639) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:397) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1429) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879) ~[spring-beans-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) ~[spring-context-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.1.RELEASE.jar:5.2.1.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.1.RELEASE.jar:2.2.1.RELEASE]
at com.example.easynotes.EasyNotesApplication.main(EasyNotesApplication.java:14) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.2.1.RELEASE.jar:2.2.1.RELEASE]
XML:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>easy-notes</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>
<name>easy-notes</name>
<description>Rest API for a Simple Note Taking Application</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.1.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.21</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.4.0</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.4.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Java Code:
package com.example.easynotes.model;
import java.math.BigDecimal;
import javax.persistence.Entity;
import javax.persistence.EntityListeners;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;
#Entity
#EntityListeners(AuditingEntityListener.class)
#Table(name = "CurrencyExchange")
public class CurrencyExchangeServiceBean {
#Id
#GeneratedValue
private int conversionid;
private String fromCurrency;
private String toCurrency;
private BigDecimal coversionMultiple;
public CurrencyExchangeServiceBean(int conversionid, String fromCurrency, String toCurrency,
BigDecimal coversionMultiple) {
super();
this.conversionid = conversionid;
this.fromCurrency = fromCurrency;
this.toCurrency = toCurrency;
this.coversionMultiple = coversionMultiple;
}
public String getFromCurrency() {
return fromCurrency;
}
public void setFromCurrency(String fromCurrency) {
this.fromCurrency = fromCurrency;
}
public String getToCurrency() {
return toCurrency;
}
public void setToCurrency(String toCurrency) {
this.toCurrency = toCurrency;
}
public int getConversionid() {
return conversionid;
}
public void setConversionid(int conversionid) {
this.conversionid = conversionid;
}
public BigDecimal getCoversionMultiple() {
return coversionMultiple;
}
public void setCoversionMultiple(BigDecimal coversionMultiple) {
this.coversionMultiple = coversionMultiple;
}
public CurrencyExchangeServiceBean() {
}
#Override
public String toString() {
return "CurrencyExchangeServiceBean [conversionid=" + conversionid + ", fromCurrency=" + fromCurrency
+ ", toCurrency=" + toCurrency + ", coversionMultiple=" + coversionMultiple + "]";
}
}
package com.example.easynotes.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import com.example.easynotes.exception.CurrencyExchangenotfound;
import com.example.easynotes.model.CurrencyExchangeServiceBean;
import com.example.easynotes.repository.CurrencyExchangeDao;
import com.example.easynotes.repository.CurrencyExchangeRepository;
#RestController
public class CurrencyExchangeController {
#Autowired
CurrencyExchangeRepository currencyExchage;
#Autowired
CurrencyExchangeDao currencyExchangeDao;
#GetMapping("/api/currencyExchange/{from}/to/{to}")
public CurrencyExchangeServiceBean getcurrencyExchange(#PathVariable String from, #PathVariable String to) {
CurrencyExchangeServiceBean c = currencyExchangeDao.gettheExchange(from, to);
if (c == null) {
throw new CurrencyExchangenotfound("no exchage found");
}
return c;
}
#PostMapping("/api/currencyExchange")
public void addcurrencytotheExchange(#RequestBody CurrencyExchangeServiceBean currencyExchangebean) {
currencyExchangeDao.addtotheExchange(currencyExchangebean);
}
}
package com.example.easynotes.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.example.easynotes.model.CurrencyExchangeServiceBean;
#Repository
public interface CurrencyExchangeRepository extends JpaRepository<CurrencyExchangeServiceBean, Integer> {
CurrencyExchangeServiceBean findByFromAndTo(String fromCurrency, String toCurrency);
}
package com.example.easynotes;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
#SpringBootApplication(scanBasePackages = { "com.example.*" })
#EnableJpaAuditing
public class EasyNotesApplication {
public static void main(String[] args) {
SpringApplication.run(EasyNotesApplication.class, args);
}
}

Answer 1

One of the best things in Spring is it's verbosity when it comes to errors.
Most of the time the errors will tell you exactly what's wrong. Like in your case.
The first line in your Stacktrace says:
(...) No property from found for type CurrencyExchangeServiceBean!
And this is exactly what I can see in the code of your CurrencyExchangeServiceBean:
private String fromCurrency;
In order to resolve your error you can now either:
a) rename the property from fromCurrency to from
b) rename the method in your Repository to findByFromCurrencyAndToCurrency
BTW. The exact same error will occur for the toCurrency vs to.