Spring数据仓库-NullPointerException

Question

我试图从cassandra键空间加载实体。 我无法找到我的代码中的错误。 我在DAO类中得到一个空指针异常。

下面是我的代码：

cassandra.properties

cassandra.contactpoints=localhost
cassandra.port=9042
cassandra.keyspacename=kssuo

DressSetDO

package com.suo.pojo;

import org.springframework.data.cassandra.mapping.Column;
import org.springframework.data.cassandra.mapping.PrimaryKey;
import org.springframework.data.cassandra.mapping.Table;

@Table(value = "dress_set_links")
public class DressSetDO {
    @PrimaryKey
    private String id;

    @Column(value = "set_name")
    private String setName;
    private String shirt;
    private String tshirt;
    private String trouser;
    @Column(value = "sun_glasses")
    private String sunGlasses;
    private String belt;
    private String shoes;
    private String watch;
    private String sweater;
    private String jacket;
    private String suits;
    private String bags;
    private String tie;
    @Column(value = "pocket_square")
    private String pocketSquare;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getSetName() {
        return setName;
    }

    public void setSetName(String setName) {
        this.setName = setName;
    }

    public String getShirt() {
        return shirt;
    }

    public void setShirt(String shirt) {
        this.shirt = shirt;
    }

    public String getTshirt() {
        return tshirt;
    }

    public void setTshirt(String tshirt) {
        this.tshirt = tshirt;
    }

    public String getTrouser() {
        return trouser;
    }

    public void setTrouser(String trouser) {
        this.trouser = trouser;
    }

    public String getSunGlasses() {
        return sunGlasses;
    }

    public void setSunGlasses(String sunGlasses) {
        this.sunGlasses = sunGlasses;
    }

    public String getBelt() {
        return belt;
    }

    public void setBelt(String belt) {
        this.belt = belt;
    }

    public String getShoes() {
        return shoes;
    }

    public void setShoes(String shoes) {
        this.shoes = shoes;
    }

    public String getWatch() {
        return watch;
    }

    public void setWatch(String watch) {
        this.watch = watch;
    }

    public String getSweater() {
        return sweater;
    }

    public void setSweater(String sweater) {
        this.sweater = sweater;
    }

    public String getJacket() {
        return jacket;
    }

    public void setJacket(String jacket) {
        this.jacket = jacket;
    }

    public String getSuits() {
        return suits;
    }

    public void setSuits(String suits) {
        this.suits = suits;
    }

    public String getBags() {
        return bags;
    }

    public void setBags(String bags) {
        this.bags = bags;
    }

    public String getTie() {
        return tie;
    }

    public void setTie(String tie) {
        this.tie = tie;
    }

    public String getPocketSquare() {
        return pocketSquare;
    }

    public void setPocketSquare(String pocketSquare) {
        this.pocketSquare = pocketSquare;
    }

    public String toString() {
        return "DressSetLinks {"
                + "id: " + id 
                + "setName:  " + setName
                + "shirt: " + shirt
                + "tshirt: " + tshirt
                + "trouser: " + trouser
                + "sunGlasses: " + sunGlasses
                + "belt: " + belt
                + "shoes: " + shoes
                + "watch: " + watch
                + "sweater: " + sweater
                + "jacket: " + jacket
                + "suits: " + suits
                + "bags: " + bags
                + "tie: " + tie
                + "pocketSquare: " + pocketSquare
                + "}";
    }
}

DressSetDAO

包com.suo.dao;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.suo.pojo.DressSetDO;
import com.suo.repo.DressSetRepository;

@Component
public class DressSetDAO {

    @Autowired
    private DressSetRepository dressRepo;

    public List<DressSetDO> search(String id) {
        List<DressSetDO> list = dressRepo.findById(id);

        System.out.println(">>> DressSet List: " + list);
        return list;
    }
}

CassandraConfig

    package com.suo.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.data.cassandra.config.CassandraClusterFactoryBean;
import org.springframework.data.cassandra.config.CassandraSessionFactoryBean;
import org.springframework.data.cassandra.config.SchemaAction;
import org.springframework.data.cassandra.config.java.AbstractCassandraConfiguration;
import org.springframework.data.cassandra.convert.CassandraConverter;
import org.springframework.data.cassandra.convert.MappingCassandraConverter;
import org.springframework.data.cassandra.core.CassandraOperations;
import org.springframework.data.cassandra.core.CassandraTemplate;
import org.springframework.data.cassandra.mapping.BasicCassandraMappingContext;
import org.springframework.data.cassandra.mapping.CassandraMappingContext;
import org.springframework.data.cassandra.repository.config.EnableCassandraRepositories;

@Configuration
@PropertySource(value = { "classpath:cassandra.properties" })
@ComponentScan(basePackages = {"com.suo.dao", "com.suo.repo", "com.suo.pojo", "com.suo.config"})
@EnableCassandraRepositories(basePackages = { "com.suo.repo" })
public class CassandraConfig extends AbstractCassandraConfiguration {

    private final String KEY_SPACE = "kssuo";

    @Autowired
    private Environment env;

    @Override
    protected String getKeyspaceName() {
        return env.getProperty("cassandra.keyspacename");
    }

    @Bean
    public CassandraClusterFactoryBean cluster() {
        CassandraClusterFactoryBean cluster = new CassandraClusterFactoryBean();
        cluster.setContactPoints(env.getProperty("cassandra.contactpoints"));
        cluster.setPort(Integer.parseInt(env.getProperty("cassandra.port")));

        return cluster;
    }

    @Bean
    public CassandraMappingContext mappingContext() {
        return new BasicCassandraMappingContext();
    }

    @Bean
    public CassandraConverter converter() {
        return new MappingCassandraConverter(mappingContext());
    }

    @Bean
    public CassandraSessionFactoryBean session() {
        CassandraSessionFactoryBean session = new CassandraSessionFactoryBean();
        session.setCluster(cluster().getObject());
        session.setKeyspaceName(getKeyspaceName());
        session.setConverter(converter());
        session.setSchemaAction(SchemaAction.NONE);

        return session;

    }

    @Bean
    public CassandraOperations cassandraTemp() throws Exception {
        return new CassandraTemplate(session().getObject());
    }

}

DressSetRepository

包com.suo.repo;

import java.io.Serializable;
import java.util.List;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.suo.pojo.DressSetDO;

@Repository
public interface DressSetRepository extends CrudRepository<DressSetDO, Serializable>{
    List<DressSetDO> findById(String id);
}

Applicaiton.java

包com.suo.main;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import com.suo.dao.DressSetDAO;

@SpringBootApplication
public class Application {

    @Autowired
    private static DressSetDAO dressDao;

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
        dressDao = new DressSetDAO();
        if(dressDao != null) {
            dressDao.search("1");
        } else {
            System.out.println("DressSetDAO bean is not autowired !");
        }
    }
}

错误

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.2.RELEASE)

2017-04-04 16:29:03.129  INFO 17034 --- [           main] com.example.Application                  : Starting Application on Rams-MacBook-Pro.local with PID 17034 (/Users/Chandra/Documents/workspace-sts-3.8.3.RELEASE/suitup.online/target/classes started by Chandra in /Users/Chandra/Documents/workspace-sts-3.8.3.RELEASE/suitup.online)
2017-04-04 16:29:03.132  INFO 17034 --- [           main] com.example.Application                  : No active profile set, falling back to default profiles: default
2017-04-04 16:29:03.176  INFO 17034 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1d7acb34: startup date [Tue Apr 04 16:29:03 PDT 2017]; root of context hierarchy
2017-04-04 16:29:03.546  WARN 17034 --- [           main] f.a.AutowiredAnnotationBeanPostProcessor : Autowired annotation is not supported on static fields: private static com.suo.dao.DressSetDAO com.example.Application.dressDao
2017-04-04 16:29:03.833  INFO 17034 --- [           main] com.datastax.driver.core.ClockFactory    : Using native clock to generate timestamps.
2017-04-04 16:29:03.978  INFO 17034 --- [           main] com.datastax.driver.core.NettyUtil       : Did not find Netty's native epoll transport in the classpath, defaulting to NIO.
2017-04-04 16:29:04.216  WARN 17034 --- [           main] com.datastax.driver.core.Cluster         : You listed localhost/0:0:0:0:0:0:0:1:9042 in your contact points, but it wasn't found in the control host's system.peers at startup
2017-04-04 16:29:04.305  INFO 17034 --- [           main] c.d.d.c.p.DCAwareRoundRobinPolicy        : Using data-center name 'datacenter1' for DCAwareRoundRobinPolicy (if this is incorrect, please provide the correct datacenter name with DCAwareRoundRobinPolicy constructor)
2017-04-04 16:29:04.306  INFO 17034 --- [           main] com.datastax.driver.core.Cluster         : New Cassandra host localhost/127.0.0.1:9042 added
2017-04-04 16:29:04.396  INFO 17034 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-04-04 16:29:04.407  INFO 17034 --- [           main] com.example.Application                  : Started Application in 11.497 seconds (JVM running for 11.768)
Exception in thread "main" java.lang.NullPointerException
    at com.suo.dao.DressSetDAO.search(DressSetDAO.java:18)
    at com.example.Application.main(Application.java:19)

Answer 1

假设您应该修改DressSetDO POJO中的代码。

在DressSetDO中，应将id更改为Long 。

@PrimaryKey
private Long id;