如何使用spring引导为mongodb创建自动生成字段
如何使用spring引导为mongodb创建自动生成字段
提问于 2016-04-06 10:51:31
我写了一些代码，我想把questionId字段作为BaseQuestion类的Autogenerated.Any解决方案。我不使用jpa jar.so，我不能使用@Generatedvalue annotation.So在这里显示这个字段是自动生成的。密码在下面。
pom.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>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>audit_project</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.scala-lang</groupId>
<artifactId>scala-library</artifactId>
<version>2.11.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>BaseQuestion.java
package model;
import java.util.List;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
@Document(collection = "basequestion")
public class BaseQuestion {
@ID
private String id;
private int questionId;
private String responseType;
private boolean required;
private boolean active;
private String questionCode;
private QuestionText questionText;
private String category;
private List<Responses> responses;
public QuestionText getQuestionText() {
return questionText;
}
public void setQuestionText(QuestionText questionText) {
this.questionText = questionText;
}
public List<Responses> getResponses() {
return responses;
}
public void setResponses(List<Responses> responses) {
this.responses = responses;
}
public int getQuestionId() {
return questionId;
}
public void setQuestionId(int questionId) {
this.questionId = questionId;
}
public String getResponseType() {
return responseType;
}
public void setResponseType(String responseType) {
this.responseType = responseType;
}
public boolean getRequired() {
return required;
}
public void setRequired(boolean required) {
this.required = required;
}
public String getQuestionCode() {
return questionCode;
}
public void setQuestionCode(String questionCode) {
this.questionCode = questionCode;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
public boolean isActive() {
return active;
}
public void setActive(boolean active) {
this.active = active;
}
}AuditProjectRepository.java
package repository;
import org.springframework.data.mongodb.repository.MongoRepository;
import model.BaseQuestion;
public interface AuditProjectRepository extends MongoRepository<BaseQuestion, String> {
public BaseQuestion findByQuestionId(int questionId);
public BaseQuestion findByQuestionCode(String questionCode);
public Long deleteByQuestionId(int questionid);
}回答 2
Stack Overflow用户
回答已采纳
发布于 2016-04-07 07:16:59
MongoDB提供了所有复杂的ObjectId生成特性，但通常只是从关系数据库中跳过，您仍然需要一个易于阅读/通信的数字标识符字段，该字段每次插入新记录时都会自动递增。
MongoDB教程的一个很好的建议是使用一个计数器集合，其id为“计数器名”，并使用一个“seq”字段来存储最后使用的数字。
在使用Spring进行开发时，这个巧妙的技巧可以编写成一个简单的服务。在这里，我使用集合名作为计数器名，因此很容易猜测/记住。
import static org.springframework.data.mongodb.core.FindAndModifyOptions.options;
import static org.springframework.data.mongodb.core.query.Criteria.where;
import static org.springframework.data.mongodb.core.query.Query.query;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoOperations;
import org.springframework.data.mongodb.core.query.Update;
import org.springframework.stereotype.Service;
import com.model.CustomSequences;
@Service
public class NextSequenceService {
@Autowired private MongoOperations mongo;
public int getNextSequence(String seqName)
{
CustomSequences counter = mongo.findAndModify(
query(where("_id").is(seqName)),
new Update().inc("seq",1),
options().returnNew(true).upsert(true),
CustomSequences.class);
return counter.getSeq();
}
}CustomSequences只是一个表示集合的简单类。请注意int数据类型的使用，这将限制最多2^31项。
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
@Document(collection = "customSequences")
public class CustomSequences {
@Id
private String id;
private int seq;
// getters and setters
}然后，在插入新条目时(借助支持)，只需在保存id字段之前设置如下所示
BaseQuestion baseQuestion = new BaseQuestion();
baseQuestion.setQuestionId(nextSequenceService.getNextSequence("customSequences"));
/* Rest all values */
baseQuestionRepository.save(baseQuestion);如果您不喜欢这种方式，那么您需要使用MongoDBEvents并使用onBeforeConvert来使用上述方法生成自动值。
上面的方法也是线程安全，因为findAndModify()是线程安全的原子方法
Stack Overflow用户
发布于 2022-06-12 08:09:53
使用字符串作为主键是个好主意。这样，您就不会配置任何东西，因为字符串是自动生成的。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/36448921
复制相关文章
相似问题
腾讯云开发者
