原因：org.springframework.dao.IncorrectResultSizeDataAccessException：错误的结果大小：Spring Data Redis

Question

我正在通过参考以下代码来开发代码： https : //www.programcreek.com/java-api-examples/? code =Just-Fun/spring-data-examples/spring-data-examples-master/jpa/query-按示例/src/test/java/example/springdata/jpa/querybyexample/UserRepositoryIntegrationTests.java 。

User.java

@Data
@RedisHash("User")
public class User {

    private @Id Long id;
    @Indexed
    private String firstname; 
    @Indexed
    private String lastname;
    private Integer age;

    public User() {}

    public User(String firstname, String lastname, Integer age) {
        super();
        this.firstname = firstname;
        this.lastname = lastname;
        this.age = age;
    }
}

UserRepository.java

public interface UserRepository extends QueryByExampleExecutor<User>, CrudRepository<User, String> {

}

RedisExampleApplication.java

@SpringBootApplication
public class RedisExampleApplication implements CommandLineRunner{
    @Autowired
    private UserRepository userRepository;

    public static void main(String[] args) {
        SpringApplication.run(RedisExampleApplication.class, args);
    }

    @Override
    public void run(String... args) throws Exception {
        userRepository.deleteAll();

        User skyler = userRepository.save(new User("Skyler", "Doe", 45));
        User walter = userRepository.save(new User("Walter", "White", 50));
        User flynn = userRepository.save(new User("Walter Jr. (Flynn)", "Kerr", 17));
        userRepository.saveAll(Arrays.asList(skyler, walter, flynn));

        long count = userRepository.count(Example.of(new User(null, "White", null)));
        System.out.println("COUNT ? "+count);


        Example<User> example = Example.of(flynn, matching().//
                withIgnorePaths("firstname", "lastname"));

        Optional<User> findOne = userRepository.findOne(example);
        System.out.println("USER ? "+findOne);
    }
}

错误：

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:816) [spring-boot-2.1.0.RELEASE.jar:2.1.0.RELEASE]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:797) [spring-boot-2.1.0.RELEASE.jar:2.1.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:324) [spring-boot-2.1.0.RELEASE.jar:2.1.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.0.RELEASE.jar:2.1.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.0.RELEASE.jar:2.1.0.RELEASE]
    at com.example.RedisExampleApplication.main(RedisExampleApplication.java:23) [classes/:na]
Caused by: org.springframework.dao.IncorrectResultSizeDataAccessException: Incorrect result size: expected 1
    at org.springframework.data.redis.repository.support.QueryByExampleRedisExecutor.findOne(QueryByExampleRedisExecutor.java:107) ~[spring-data-redis-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_162]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_162]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_162]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:359) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:644) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:608) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$invoke$3(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at com.sun.proxy.$Proxy57.findOne(Unknown Source) ~[na:na]
    at com.example.RedisExampleApplication.run(RedisExampleApplication.java:45) [classes/:na]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:813) [spring-boot-2.1.0.RELEASE.jar:2.1.0.RELEASE]
    ... 5 common frames omitted

Answer 1

该问题可能是由于：

Optional<User> findOne = userRepository.findOne(example);

在这里，您使用的是findOne方法，但似乎得到的结果不止一个。 因此，可以使用find方法或修改搜索条件以确保获得单个结果。