java中的tree组件

 

在开发系统的时候，尤其是前端需要展现一棵树的时候，经常需要构建一棵树来展现层级结构。

java中swing自带的tree就能满足这些需求，各种遍历方式都有。

 

参考资料： https://docs.oracle.com/javase/tutorial/uiswing/components/tree.html 

 

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import java.util.Arrays;
import java.util.Enumeration;

import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeNode;

/**
 * @ClassName: TreeExample
 * @author kanpiaoxue
 * @version 1.0
 * @CreateTime: 2020/05/20 14:22:41
 * @Description:
 */
public class TreeExample {

    private static final DefaultMutableTreeNode root =
            new DefaultMutableTreeNode(new BookInfo(1, "name-root"));
    private static final DefaultMutableTreeNode note01 =
            new DefaultMutableTreeNode(new BookInfo(2, "name-01"));
    private static final DefaultMutableTreeNode note02 =
            new DefaultMutableTreeNode(new BookInfo(3, "name-02"));
    private static final DefaultMutableTreeNode note03 =
            new DefaultMutableTreeNode(new BookInfo(4, "name-03"));
    private static final DefaultMutableTreeNode note04 =
            new DefaultMutableTreeNode(new BookInfo(5, "name-04"));
    private static final DefaultMutableTreeNode note05 =
            new DefaultMutableTreeNode(new BookInfo(6, "name-05"));
    private static final DefaultMutableTreeNode note06 =
            new DefaultMutableTreeNode(new BookInfo(7, "name-06"));
    private static final DefaultMutableTreeNode note07 =
            new DefaultMutableTreeNode(new BookInfo(8, "name-07"));
    private static final DefaultMutableTreeNode note08 =
            new DefaultMutableTreeNode(new BookInfo(9, "name-08"));
    private static final DefaultMutableTreeNode note09 =
            new DefaultMutableTreeNode(new BookInfo(10, "name-09"));
    private static final DefaultMutableTreeNode note10 =
            new DefaultMutableTreeNode(new BookInfo(11, "name-10"));

    private static final Gson gson = new GsonBuilder()
            .registerTypeAdapter(DefaultMutableTreeNode.class, new DefaultMutableTreeNodeSerializer())
            .registerTypeAdapter(DefaultMutableTreeNode.class, new DefaultMutableTreeNodeDeserializer())
            .setPrettyPrinting().create();

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        DefaultMutableTreeNode root = createNodes();

        Enumeration<DefaultMutableTreeNode> rootEnumeration = root.breadthFirstEnumeration();
        while (rootEnumeration.hasMoreElements()) {
            DefaultMutableTreeNode n = rootEnumeration.nextElement();
            System.out.println("-->" + n);
        }

        System.out.println("root:" + note10.getRoot());

        TreeNode[] path = note10.getPath();
        Arrays.stream(path).forEach(n -> {
            System.out.println(n);
        });

        String json = gson.toJson(root);
        System.out.println(json);

        DefaultMutableTreeNode rootClone = gson.fromJson(json, DefaultMutableTreeNode.class);
        System.out.println(rootClone.getDepth());

    }

    private static DefaultMutableTreeNode createNodes() {
        /**
         * <pre>
         * 树的结构：
         * https://www.draw.io/?lightbox=1&highlight=0000ff&edit=_blank&layers=1&nav=1&title=Untitled%20Diagram.drawio#R5ZlBb5swFMc%2FDcdK2CaEXJt1a6VNmsahZyu8AhPwkGNC0k8%2FJxgIc5exw2KnPQF%2FP4P94%2F31jPHYutx%2FEbzOvmEChUf9ZO%2BxTx6lNFoxdTgqh04hPgk6JRV5orVRiPNX6AO12uQJbCeBErGQeT0VN1hVsJETjQuB7TTsBYvpU2uegiHEG16Y6nOeyKxTI7oc9UfI06x%2FMglXXUvJ%2B2A9k23GE2zPJPbgsbVAlN1ZuV9DcaTXc%2Bn6ff5D6zAwAZWc0yF6%2Ff6SyOcYszL%2BsX6qavb4dKdfz44XjZ6wHqw89AQENlUCx5v4HrtHITNMseLFV8RaiUSJP0HKg353vJGopEyWhW7t7giJAXocuZa22IgNXBhunwFcpCAvxNGBr8pMwBKkOKh%2BAgou8910HFxnSDrEjRDVieb4D0wXf2d6hBHrywordbi%2FRcyBTczLD4M5tImZrD4MZxJZBW1wJgbokeoRUZvlEuKanybfqgL8FsEdCAn7ywzNKfcd%2BuKlyzf19XU71sIhJjurg4H%2FvyhFBqZTCXWNVGQb1O3bNpxpW6uuDQ3MzLlcZNR2MpqmDZ2jFAS2KZEZq3HHPRvMLbVWV%2BiBwTmwno5DWjljWkINTEvnMDngWnPhdmuupXNd67%2F9bq7jWjMdL21WXCcd74hzrn0H2w%2F%2B3Hy0ugFB3sEOxGzSdvcgfIP0wjnr269E9PYrEZn70UetliJifvatrCfkbyujRWg9H03b9p5xB1NofaeGmJ8jkXVKall7vXRSl%2BN%2FsFPb2e9E9vAL
         * </pre>
         */

        root.add(note01);
        note01.add(note02);
        note01.add(note03);
        note01.add(note04);

        note02.add(note05);

        note05.add(note08);
        note05.add(note09);

        note09.add(note10);

        note03.add(note06);
        note04.add(note07);
        return root;
    }
}

输出内容：

写道

-->BookInfo [id=1, name=name-root]
-->BookInfo [id=2, name=name-01]
-->BookInfo [id=3, name=name-02]
-->BookInfo [id=4, name=name-03]
-->BookInfo [id=5, name=name-04]
-->BookInfo [id=6, name=name-05]
-->BookInfo [id=7, name=name-06]
-->BookInfo [id=8, name=name-07]
-->BookInfo [id=9, name=name-08]
-->BookInfo [id=10, name=name-09]
-->BookInfo [id=11, name=name-10]
root:BookInfo [id=1, name=name-root]
BookInfo [id=1, name=name-root]
BookInfo [id=2, name=name-01]
BookInfo [id=3, name=name-02]
BookInfo [id=6, name=name-05]
BookInfo [id=10, name=name-09]
BookInfo [id=11, name=name-10]
{
"allowsChildren": true,
"userObject": {
"id": 1,
"name": "name-root"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 2,
"name": "name-01"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 3,
"name": "name-02"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 6,
"name": "name-05"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 9,
"name": "name-08"
}
},
{
"allowsChildren": true,
"userObject": {
"id": 10,
"name": "name-09"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 11,
"name": "name-10"
}
}
]
}
]
}
]
},
{
"allowsChildren": true,
"userObject": {
"id": 4,
"name": "name-03"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 7,
"name": "name-06"
}
}
]
},
{
"allowsChildren": true,
"userObject": {
"id": 5,
"name": "name-04"
},
"children": [
{
"allowsChildren": true,
"userObject": {
"id": 8,
"name": "name-07"
}
}
]
}
]
}
]
}
5

  

参考资料：

《How to serialize DefaultMutableTreeNode (Java) to JSON?》 https://stackoverflow.com/questions/53997112/how-to-serialize-defaultmutabletreenode-java-to-json

 

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

import java.util.Collections;

import javax.swing.tree.DefaultMutableTreeNode;

public class DefaultMutableTreeNodeSerializer implements JsonSerializer<DefaultMutableTreeNode> {


    /* (non-Javadoc)
     * @see com.google.gson.JsonSerializer#serialize(java.lang.Object, java.lang.reflect.Type, com.google.gson.JsonSerializationContext)
     */
    @SuppressWarnings("unchecked")
    @Override
    public JsonElement serialize(DefaultMutableTreeNode src, java.lang.reflect.Type typeOfSrc,
            JsonSerializationContext context) {
        JsonObject jsonObject = new JsonObject();
        jsonObject.addProperty("allowsChildren", src.getAllowsChildren());
        jsonObject.add("userObject", context.serialize(src.getUserObject()));
        if (src.getChildCount() > 0) {
            jsonObject.add("children", context.serialize(Collections.list(src.children())));
        }
        return jsonObject;
    }
}

 

 

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;

import java.util.List;

import javax.swing.tree.DefaultMutableTreeNode;


public class DefaultMutableTreeNodeDeserializer implements JsonDeserializer<DefaultMutableTreeNode> {


    private static class POJO {

        private boolean allowsChildren;
        private Object userObject;
        private List<POJO> children;
        // no need for: POJO parent

        public DefaultMutableTreeNode toDefaultMutableTreeNode() {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode();
            node.setAllowsChildren(allowsChildren);
            node.setUserObject(userObject);
            if (children != null) {
                for (POJO child : children) {
                    node.add(child.toDefaultMutableTreeNode()); // recursion!
                    // this did also set the parent of the child-node
                }
            }
            return node;
        }

        // Following setters needed by Gson's deserialization:

        @SuppressWarnings("unused")
        public void setAllowsChildren(boolean allowsChildren) {
            this.allowsChildren = allowsChildren;
        }

        @SuppressWarnings("unused")
        public void setUserObject(Object userObject) {
            this.userObject = userObject;
        }

        @SuppressWarnings("unused")
        public void setChildren(List<POJO> children) {
            this.children = children;
        }
    }

    /* (non-Javadoc)
     * @see com.google.gson.JsonDeserializer#deserialize(com.google.gson.JsonElement, java.lang.reflect.Type, com.google.gson.JsonDeserializationContext)
     */
    @Override
    public DefaultMutableTreeNode deserialize(JsonElement json, java.lang.reflect.Type typeOfT,
            JsonDeserializationContext context) throws JsonParseException {
        return context.<POJO>deserialize(json, POJO.class).toDefaultMutableTreeNode();
    }
}

 

 

public class BookInfo {
    private Integer id;
    private String name;

    /**
     * @param id
     * @param name
     */
    public BookInfo(Integer id, String name) {
        super();
        this.id = id;
        this.name = name;
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        BookInfo other = (BookInfo) obj;
        if (name == null) {
            if (other.name != null) {
                return false;
            }
        } else if (!name.equals(other.name)) {
            return false;
        }
        return true;
    }

    /**
     * @return the id
     */
    public Integer getId() {
        return id;
    }

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    /**
     * @param id
     *            the id to set
     */
    public void setId(Integer id) {
        this.id = id;
    }

    /**
     * @param name
     *            the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "BookInfo [id=" + id + ", name=" + name + "]";
    }

}