所以我正在尝试将 MongoJack 与 MongoDB 和 jackson 一起使用，以从 MongoDB 访问数据并将其转换为 POJO。即使我以最简单的方式进行操作，并且此时基本上只是复制粘贴了 mongojack 教程，我似乎仍在挣扎 (http://mongojack.org)

我试图获取对象的代码:

    public static void main(String[] args) {

    MongoClient mongoClient = new MongoClient(Arrays.asList(new ServerAddress("localhost", 27017)));
    DB db1 = mongoClient.getDB("test1");
    DBCollection coll = db1.getCollection("things1");
    JacksonDBCollection<BlogPost, String> Jcoll =
            JacksonDBCollection.wrap(coll,
                    BlogPost.class,
                    String.class);


    BlogPost blogPost = new BlogPost();
    WriteResult<BlogPost, String> result = Jcoll.insert(blogPost);


    String savedId = result.getSavedId();

    System.out.println(savedId);


    BlogPost test3 = Jcoll.findOneById(savedId);


}

和博客文章类的代码

public class BlogPost {

    @ObjectId
    private String _id;

    @ObjectId
    public String get_id() {
        return _id;
    }
    @ObjectId
    public void set_id(String _id) {
        this._id = _id;
    }
}

我得到的错误是:

Exception in thread "main" java.lang.IllegalAccessError: tried to access method org.bson.types.ObjectId.(III)V from class org.mongojack.internal.stream.ObjectIdConvertor.

现在已经尝试了很多不同的变体并且添加到数据库等工作正常，只是没有从 MongoDB 创建对象。

编辑:

Exception in thread "main" java.lang.IllegalAccessError: tried to access method org.bson.types.ObjectId.<init>(III)V from class org.mongojack.internal.stream.ObjectIdConvertor
at org.mongojack.internal.stream.ObjectIdConvertor.convert(ObjectIdConvertor.java:30)
at org.mongojack.internal.stream.DBDecoderBsonParser.getEmbeddedObject(DBDecoderBsonParser.java:70)
at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:36)
at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:11)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:525)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:99)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:242)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:118)
at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:2965)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:1626)
at org.mongojack.internal.stream.JacksonDBDecoder.decode(JacksonDBDecoder.java:77)
at org.mongojack.internal.stream.JacksonDBDecoder.decode(JacksonDBDecoder.java:64)
at com.mongodb.DBDecoderAdapter.decode(DBDecoderAdapter.java:49)
at com.mongodb.DBDecoderAdapter.decode(DBDecoderAdapter.java:29)
at com.mongodb.connection.ReplyMessage.<init>(ReplyMessage.java:57)
at com.mongodb.connection.QueryProtocol.receiveMessage(QueryProtocol.java:290)
at com.mongodb.connection.QueryProtocol.execute(QueryProtocol.java:229)
at com.mongodb.connection.QueryProtocol.execute(QueryProtocol.java:38)
at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:155)
at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:219)
at com.mongodb.connection.DefaultServerConnection.query(DefaultServerConnection.java:166)
at com.mongodb.operation.FindOperation$1.call(FindOperation.java:397)
at com.mongodb.operation.FindOperation$1.call(FindOperation.java:394)
at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:195)
at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:168)
at com.mongodb.operation.FindOperation.execute(FindOperation.java:394)
at com.mongodb.operation.FindOperation.execute(FindOperation.java:57)
at com.mongodb.Mongo.execute(Mongo.java:738)
at com.mongodb.Mongo$2.execute(Mongo.java:725)
at com.mongodb.DBCursor.initializeCursor(DBCursor.java:815)
at com.mongodb.DBCursor.hasNext(DBCursor.java:149)
at org.mongojack.DBCursor.hasNext(DBCursor.java:348)
at org.mongojack.JacksonDBCollection.findOne(JacksonDBCollection.java:1364)
at org.mongojack.JacksonDBCollection.findOne(JacksonDBCollection.java:1334)
at org.mongojack.JacksonDBCollection.findOneById(JacksonDBCollection.java:1282)
at org.mongojack.JacksonDBCollection.findOneById(JacksonDBCollection.java:1269)
at com.tapdaq.restapi.MongoConfiguration.main(MongoConfiguration.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

进程结束，退出代码为 1

任务:

<?xml version="1.0" encoding="UTF-8"?>

http://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0

<groupId>com.tapdaq.restapi</groupId>
<artifactId>restapi</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
    <dropwizard.version>0.8.1</dropwizard.version>
</properties>

<build><plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>2.4</version>
        <configuration>
            <archive>
                <manifest>
                    <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                </manifest>
            </archive>
        </configuration>
    </plugin>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.3</version>
        <configuration>
            <createDependencyReducedPom>true</createDependencyReducedPom>
            <filters>
                <filter>
                    <artifact>*:*</artifact>
                    <excludes>
                        <exclude>META-INF/*.SF</exclude>
                        <exclude>META-INF/*.DSA</exclude>
                        <exclude>META-INF/*.RSA</exclude>
                    </excludes>
                </filter>
            </filters>
        </configuration>
        <executions>
            <execution>
                <phase>package</phase>
                <goals>
                    <goal>shade</goal>
                </goals>
                <configuration>
                    <transformers>
                        <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                        <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                            <mainClass>com.tapdaq.restapi.HelloWorldApplication</mainClass>
                        </transformer>
                    </transformers>
                </configuration>
            </execution>
        </executions>
    </plugin>

</plugins></build>
<dependencies>

    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>mongo-java-driver</artifactId>
        <version>3.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.mongodb</groupId>
        <artifactId>bson</artifactId>
        <version>2.13.2</version>
    </dependency>
    <dependency>
        <groupId>org.mongojack</groupId>
        <artifactId>mongojack</artifactId>
        <version>2.1.0</version>
    </dependency>


    <dependency>

        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-core</artifactId>
        <version>${dropwizard.version}</version>
    </dependency>
</dependencies>

最佳答案

这很可能是依赖版本问题。您正在指定一些与您正在使用的 MongoJack 版本不兼容的库。您应该删除以下依赖项:

<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.0.2</version>
</dependency>
<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>bson</artifactId>
    <version>2.13.2</version>
</dependency>

并让它们从 MongoJack 依赖项传递过来。

关于java.lang.IllegalAccessError 当试图从 MongoDB 制作 POJO 时？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31147222/