RestController 在没有堆栈跟踪的情况下返回 500 错误答案

【问题标题】：RestController returns 500 error without stack traceRestController 在没有堆栈跟踪的情况下返回 500 错误
【发布时间】：2015-11-06 14:26:05
【问题描述】：

我这样定义UserController和UserRepository和User

UserController.java

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.lang3.RandomStringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.crypto.codec.Hex;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.zusn.domain.User;
import com.zusn.repository.UserRepository;

@RestController
@RequestMapping(value = "/user")
public class UserController {
    @Autowired
    private UserRepository userRepository;

    @RequestMapping(value = "/create", method = RequestMethod.POST)
    public User createUser(@RequestBody User newUesr) throws NoSuchAlgorithmException{
        User user = userRepository.findByUidAndDevice(newUesr.getUid(), newUesr.getDevice());
        if(user == null){
            MessageDigest md = MessageDigest.getInstance("SHA");
            Long now = System.nanoTime();
            md.update(now.byteValue());
            String random = RandomStringUtils.randomAlphabetic(32);
            md.update(random.getBytes());
            newUesr.setConsumerKey(String.valueOf(Hex.encode(md.digest())));
            return userRepository.save(newUesr);
        }else{
            return user;
        }
    }
}

UserRepository.java

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;

import com.zusn.domain.Devices;
import com.zusn.domain.Providers;
import com.zusn.domain.User;

@Repository
public interface UserRepository extends JpaRepository<User, Long>{
    /**
     * 
     * @param uid UID
     * @param provider Profider ex) twitter, google+, facebook
     * @return User
     */
    public User findByUidAndProvider(@Param("uid") String uid, @Param("provider") Providers provider);

    /**
     * 
     * @param uid UID
     * @param devices Device ex) iOS, Android
     * @return User
     */
    public User findByUidAndDevice(@Param("uid")String uid, @Param("device") Devices device);
}

用户.java

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;


@Entity
@Table(name = "users")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false)
    private Long id;

    @Column(name = "uid", nullable = false)
    private String uid;

    @Column(name = "provider")
    private Providers provider;

    @Column(name = "device", nullable = false)
    private Devices device;

    @Column(name = "consumer_key", nullable = false, unique = true)
    private String consumerKey;

    @OneToOne(cascade = CascadeType.ALL, fetch=FetchType.LAZY)
    private Profile profile;



    public User() {
        super();
    }

    public User(String uid, Providers providers, String consumerKey) {
        super();
        this.uid = uid;
        this.provider = providers;
        this.consumerKey = consumerKey;
    }

    public String getConsumerKey() {
        return consumerKey;
    }

    public void setConsumerKey(String consumerKey) {
        this.consumerKey = consumerKey;
    }

    public User(Providers provider){
        this.provider=provider;
    }

    public Long getId() {
        return id;
    }

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

    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    public Providers getProvider() {
        return provider;
    }

    public void setProvider(Providers provider) {
        this.provider = provider;
    }

    public Profile getProfile() {
        return profile;
    }

    public void setProfile(Profile profile) {
        this.profile = profile;
    }

    public Devices getDevice() {
        return device;
    }

    public void setDevice(Devices device) {
        this.device = device;
    }

}

当用户不存在时，即处理第一个if 语句，此方法返回新的User 对象。但是当用户已经存在时，它会返回状态码 500。
然后它在返回 500 错误时没有打印堆栈跟踪。

所以我不确定它为什么返回 500 错误。请告诉我这段代码有什么问题以及为什么它返回 500 错误。

【问题讨论】：

标签： java spring-boot

【解决方案1】：

首先，我认为您可以处理 Spring Data JPA 层抛出的 DataAccessException。对于 500 错误，我认为这可能是延迟加载的问题。我认为当您第一次在数据库中插入对象实体时，这是一种不同的行为。你用的是什么服务器？它是一只雄猫吗？如果是这样，您如何监控您的日志？根据您的配置，一些日志在标准 catalina.out 文件中不可见。您需要签入 localhost 日志文件以查看堆栈跟踪。

【讨论】：

【解决方案2】：

如果没有堆栈跟踪，就很难猜出问题所在。也许@NoOne 是对的，但也许你在旧开发留下的数据库中有一个独特的约束。

如果看不到stacktrace客户端，可以输入this snipped获取stacktrace服务器端。因为 5xx 错误只是说明这个问题。服务器出错了。

【讨论】：