java - 从 csv 平面文件填充 Java Bean 树结构

Question

我目前正在尝试从一个 csv 格式的平面描述文件中构建 Java 中的 bean 类列表。具体来说:

这是 csv 文件的结构:

MES_ID;GRP_PARENT_ID;GRP_ID;ATTR_ID
M1    ;             ;G1    ;A1
M1    ;             ;G1    ;A2
M1    ;G1           ;G2    ;A3
M1    ;G1           ;G2    ;A4
M1    ;G2           ;G3    ;A5
M1    ;             ;G4    ;A6
M1    ;             ;G4    ;A7
M1    ;             ;G4    ;A8
M2    ;             ;G1    ;A1
M2    ;             ;G1    ;A2
M2    ;             ;G2    ;A3
M2    ;             ;G2    ;A4

它对应的层次数据结构:

M1
---G1
------A1
------A2
------G2
---------A3
---------A4
---------G3
------------A5
---G4
------A7
------A8
M2
---G1
------A1
------A2
---G2
------A3
------A4

备注:

• 一条消息M可以有无限多个组G和属性A

• 群G可以有无限个属性和无限个下群，每个下群都有下群

蜜蜂说，我正在尝试阅读此平面 csv 描述以将其存储在这种 bean 结构中:

Map<String, MBean> messages = new HashMap<String, Mbean>();

==

public class MBean {
   private String mes_id;
   private Map<String, GBean> groups;
}

public class GBean {
   private String grp_id;
   private Map<String, ABean> attributes;
   private Map<String, GBean> underGroups;
}

public class ABean {
   private String attr_id;
}

顺序读取csv文件是可以的，我一直在研究如何使用递归来存储描述数据，但找不到方法。

提前感谢您提供任何算法想法。

我希望它会让你有心情去思考这个……我不得不承认我没有想法:s

Answer 1

这是一个解决方案，添加评论留作练习......

public class Test {

public static void main(String[] args) {
    List<Record> records = new ArrayList<Record>() {
        {
            add(new Record("M1", "", "G1", "A1"));
            add(new Record("M1", "", "G1", "A2"));

            add(new Record("M1", "G1", "G2", "A3"));
            add(new Record("M1", "G1", "G2", "A4"));
        }
    };

    MessageContainer messageContainer = new MessageContainer();
    for (Record record : records) {
        messageContainer.addOrUpdateMessage(record);
    }

}

private static class Record {

    final String messageId;
    final String parentGroupId;
    final String groupId;
    final String attributeId;

    public Record(String messageId, String parentGroupId, String groupId, String attributeId) {
        super();
        this.messageId = messageId;
        this.parentGroupId = parentGroupId;
        this.groupId = groupId;
        this.attributeId = attributeId;
    }

}

private static class MessageContainer {

    Map<String, MBean> messages = new HashMap<String, MBean>();

    public void addOrUpdateMessage(Record record) {
        MBean mBean = messages.get(record.messageId);
        if (mBean == null) {
            mBean = new MBean(record.messageId);
            messages.put(record.messageId, mBean);
        }
        mBean.addOrUpdateGroup(record);
    }
}

private static class MBean {
    private final String mes_id;
    private final Map<String, GBean> groups = new HashMap<String, GBean>();

    public MBean(String mesId) {
        super();
        mes_id = mesId;
    }

    public void addOrUpdateGroup(Record record) {
        String groupToHandle = (record.parentGroupId != "" ? record.parentGroupId : record.groupId);
        GBean gBean = groups.get(groupToHandle);
        if (gBean == null) {
            gBean = new GBean(groupToHandle);
            groups.put(groupToHandle, gBean);
        }
        gBean.addOrUpdateGroup(record);
    }
}

private static class GBean {
    private final String groupId;
    private final Map<String, ABean> attributes = new HashMap<String, ABean>();
    private final Map<String, GBean> underGroups = new HashMap<String, GBean>();

    public GBean(String groupId) {
        super();
        this.groupId = groupId;
    }

    public void addOrUpdateGroup(Record record) {
        if (groupId == record.parentGroupId) {

            GBean child = underGroups.get(record.groupId);
            if (child == null) {
                child = new GBean(record.groupId);
                underGroups.put(record.groupId, child);
            }
            child.addOrUpdateGroup(record);

        } else if (groupId == record.groupId) {
            attributes.put(record.attributeId, new ABean(record.attributeId));
        } else {
            throw new RuntimeException("Unexpected state [recordParentGroupId="+record.parentGroupId+", recordGroupId="+record.groupId+", groupId="+groupId+"]");

        }

    }

    private static class ABean {
        private final String attr_id;
        public ABean(String attrId) {
            super();
            attr_id = attrId;
        }

    }
}
}