如何修复“导入com.dyuproject无法解析”错误

我是Java的新手，尤其是Maven的新手，尤其是protostuff项目（protostuff网站）。我需要使用protostuff将XML序列化/反序列化为Google的protobuf格式。我尝试使用protobuf-java-format软件包，但是反序列化中有一个已记录的错误，这对我来说是个阻碍（问题37）。

到目前为止，我已经完成了以下工作：

1. 下载protostuff-1.3.1并解压缩。
2. 然mvn integration-test，mvn install并mvn package和所有步骤成功。
3. 然后，我创建了一个新的maven项目，并包含一个此处所述的原型。

4. 然后，我修改了pom.xml并protostuff:compile按照上述链接中的描述运行原型，生成了以下Person.java文件

   // Generated by http://code.google.com/p/protostuff/ ... DO NOT EDIT!
   // Generated from foo.proto
   
   package com.example.foo;
   
   import java.io.Externalizable;
   import java.io.IOException;
   import java.io.ObjectInput;
   import java.io.ObjectOutput;
   
   import com.dyuproject.protostuff.ByteString;
   import com.dyuproject.protostuff.GraphIOUtil;
   import com.dyuproject.protostuff.Input;
   import com.dyuproject.protostuff.Message;
   import com.dyuproject.protostuff.Output;
   import com.dyuproject.protostuff.Schema;
   import com.dyuproject.protostuff.UninitializedMessageException;
   
   public final class Person implements Externalizable, Message<Person>, Schema<Person>
   {
       public enum Gender implements com.dyuproject.protostuff.EnumLite<Gender>
       {
           MALE(1),
           FEMALE(2);
   
           public final int number;
   
           private Gender (int number)
           {
               this.number = number;
           }
   
           public int getNumber()
           {
               return number;
           }
   
           public static Gender valueOf(int number)
           {
               switch(number) 
               {
                   case 1: return MALE;
                   case 2: return FEMALE;
                   default: return null;
               }
           }
       }
   
   
       public static Schema<Person> getSchema()
       {
           return DEFAULT_INSTANCE;
       }
   
       public static Person getDefaultInstance()
       {
           return DEFAULT_INSTANCE;
       }
   
       static final Person DEFAULT_INSTANCE = new Person();
   
       static final String DEFAULT_MOTTO = ByteString.stringDefaultValue("When the cat is away, the mouse is alone!");
       static final Gender DEFAULT_GENDER = Gender.MALE;
   
       private Integer id;
       private String name;
       private String motto = DEFAULT_MOTTO;
       private Gender gender;
   
       public Person()
       {
   
       }
   
       public Person(
           Integer id
       )
       {
           this.id = id;
       }
   
       // getters and setters
   
       // id
   
       public Integer getId()
       {
           return id;
       }
   
       public void setId(Integer id)
       {
           this.id = id;
       }
   
       // name
   
       public String getName()
       {
           return name;
       }
   
       public void setName(String name)
       {
           this.name = name;
       }
   
       // motto
   
       public String getMotto()
       {
           return motto;
       }
   
       public void setMotto(String motto)
       {
           this.motto = motto;
       }
   
       // gender
   
       public Gender getGender()
       {
           return gender == null ? Gender.MALE : gender;
       }
   
       public void setGender(Gender gender)
       {
           this.gender = gender;
       }
   
       // java serialization
   
       public void readExternal(ObjectInput in) throws IOException
       {
           GraphIOUtil.mergeDelimitedFrom(in, this, this);
       }
   
       public void writeExternal(ObjectOutput out) throws IOException
       {
           GraphIOUtil.writeDelimitedTo(out, this, this);
       }
   
       // message method
   
       public Schema<Person> cachedSchema()
       {
           return this;
       }
   
       // schema methods
   
       public Person newMessage()
       {
           return new Person();
       }
   
       public Class<Person> typeClass()
       {
           return Person.class;
       }
   
       public String messageName()
       {
           return Person.class.getSimpleName();
       }
   
       public String messageFullName()
       {
           return Person.class.getName();
       }
   
       public boolean isInitialized(Person message)
       {
           return 
               message.id != null;
       }
   
       public void mergeFrom(Input input, Person message) throws IOException
       {
           for(int number = input.readFieldNumber(this);; number = input.readFieldNumber(this))
           {
               switch(number)
               {
                   case 0:
                       return;
                   case 1:
                       message.id = input.readInt32();
                       break;
                   case 2:
                       message.name = input.readString();
                       break;
                   case 3:
                       message.motto = input.readString();
                       break;
                   case 4:
                       message.gender = Gender.valueOf(input.readEnum());
                       break;
                   default:
                       input.handleUnknownField(number, this);
               }   
           }
       }
   
   
       public void writeTo(Output output, Person message) throws IOException
       {
           if(message.id == null)
               throw new UninitializedMessageException(message);
           output.writeInt32(1, message.id, false);
   
           if(message.name != null)
               output.writeString(2, message.name, false);
   
           if(message.motto != null && message.motto != DEFAULT_MOTTO)
               output.writeString(3, message.motto, false);
   
           if(message.gender != null)
                output.writeEnum(4, message.gender.number, false);
       }
   
       public String getFieldName(int number)
       {
           switch(number)
           {
               case 1: return "id";
               case 2: return "name";
               case 3: return "motto";
               case 4: return "gender";
               default: return null;
           }
       }
   
       public int getFieldNumber(String name)
       {
           final Integer number = __fieldMap.get(name);
           return number == null ? 0 : number.intValue();
       }
   
       private static final java.util.HashMap<String,Integer> __fieldMap = new java.util.HashMap<String,Integer>();
       static
       {
           __fieldMap.put("id", 1);
           __fieldMap.put("name", 2);
           __fieldMap.put("motto", 3);
           __fieldMap.put("gender", 4);
       }
   
   }
   

我正在Eclipse（Luna版本）中构建整个项目，它为上述文件给出了错误“无法解析导入com.dyuproject”。我不明白为什么它会给出错误或如何找到/安装该软件包，以便Eclipse可以看到它。Maven应该已经建立/提供了吗？

我在VirtualBox VM上运行CentOS版本6.4（最终版）：

uname -a Linux localhost.localdomain 2.6.32-358.18.1.el6.x86_64 #1 SMP Wed Aug 28 17:19:38 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux `