MongoDB没有找到能够从类型org.bson.types.ObjectId转换为java.lang.Long类型的转换器

Question

我为Postgres和MongoDB使用的客户提供以下模型。它适用于Postgres，但是当我想列出MongoDB中的所有客户时，我收到了这个错误：

  

org.springframework.core.convert.ConverterNotFoundException：没有   转换器发现能够从类型转换   org.bson.types.ObjectId输入java.lang.Long

这是我的模特课：

package com.example.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;

import org.apache.commons.lang.builder.ToStringBuilder;

@Entity
@XmlRootElement(name = "customer")
@Table(name = "customer")
public class Customer implements java.io.Serializable {

    private static final long serialVersionUID = 1L;
    private Long id;
    private String firstName;
    private String lastName;

    public Customer() {
    }

    public Customer(String fn, String ln) {
        this.firstName = fn;
        this.lastName = ln;
    }

    public Customer(Long id, String firstName, String lastName) {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
    }

    @XmlAttribute(name = "id", required = false)
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    public Long getId() {
        return this.id;
    }

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

    @XmlAttribute(name = "first-name", required = false)
    @Column(name = "first_name", nullable = false)
    public String getFirstName() {
        return this.firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }


    @XmlAttribute(name = "last-name", required = false)
    @Column(name = "last_name", nullable = false)
    public String getLastName() {
        return this.lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this);
    }
}

以下是我的CustomerService，用于检索所有客户：

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;

import javax.inject.Inject;

import org.springframework.context.annotation.Import;
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.stereotype.Service;

import com.example.model.Customer;
import com.example.service.CustomerService;

@Service
@Import({ MongoConfiguration.class })
public class MongoCustomerService implements CustomerService{   

    @Inject MongoTemplate mongoTemplate;

    Class<Customer> entityClass = Customer.class;

    @Override
    public Collection<Customer> getAllCustomers() {
        try {
             List<Customer> allCustomers = mongoTemplate.findAll(entityClass);
             return allCustomers;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

我的pom.xml：

          </dependency>
            <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-mongodb</artifactId>
            <version>1.3.3.RELEASE</version>
        </dependency>

Answer 1

我将id从Long更改为BigInteger，并按照文档进行操作。

Answer 2

您的id字段需要调用_id，或者需要使用@Id对其进行注释。请参阅the documentation。

Answer 3

以下是我在Grails（2.3.4）上运行mongo所采取的三个步骤：

我有mongo db实例与人员集合。

1。 DataSource.groovy中

grails {
    mongo {
        host = "localhost"
        port = 27017
        databaseName = "<db Name>"
    }
}

2。 BuildConfig.groovy

plugins {

        // plugins for the build system only
        build ":tomcat:7.0.47"

        // plugins for the compile step
        compile ":scaffolding:2.0.1"
        compile ':cache:1.1.1'
        **compile ":mongodb:1.3.1"**

        // plugins needed at runtime but not for compilation
        runtime ":hibernate:3.6.10.6" // or ":hibernate4:4.1.11.6"
        runtime ":database-migration:1.3.8"
        runtime ":jquery:1.10.2.2"
        runtime ":resources:1.2.1"
     }

3。域名定义：

package mongo
class Person{
String id
Sting name

static mapWith="mongo"

static mapping={
 collection "persons"
 database "<dbName>"

}
}

Answer 4

使用@Id创建字段_id和注释。将类型设为大整数

Answer 5

在我的表格中显示不同类型的ID时出现错误。删除所有错误的ID后，我的应用可以正常运行。

Answer 6

import org.bson.types.ObjectId;

然后 使用ObjectId _id代替Long ID；

@Id
private ObjectId _id;