我是 D3 api 的新手。我必须制作一个树状结构，它有一个 json 文件，其中的值是硬编码的，我有一个 servlet，我从数据库中获取一些值，我必须在其中动态地制作 json servlet 并且必须将响应设置回 D3。这是我编写 d3 的 html。我可以使用 java 类创建 json，但不能从 D3.js 调用它，这是我的 java 文件和创建的 json 以及我的 html 文件.....
public class Test {
public static void main(String[] args)
{
// hierarchical data in a flattened list
String[][] data = {
{"Toyota", "Gas", "Compact", "Corolla"},
{"Toyota", "Gas", "Compact", "Camry"},
{"Toyota", "Hybrid", "Compact", "Prius"},
{"Honda", "Gas", "Compact", "Civic"}
};
TreeManager treeManager = new TreeManager();
for(String[] row : data)
{
// build the path to our items in the tree
List<String> path = new ArrayList<String>();
for(String item : row)
{
// add this item to our path
path.add(item);
// will add it unless an Item with this name already exists at this path
treeManager.addData(treeManager, path);
}
}
treeManager.getData(data[0]).putValue("MPG", 38);
treeManager.getData(data[1]).putValue("MPG", 28);
Gson gson = new Gson();
System.out.println(gson.toJson(treeManager));
}
/**
* This base class provides the hierarchical property of
* an object that contains a Map of child objects of the same type.
* It also has a field - Name
*
*/
public static abstract class TreeItem implements Iterable<TreeItem>{
private Map<String, TreeItem> children;
private String name;
public TreeItem() {
children = new HashMap<String, TreeItem>();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void addChild(String key, TreeItem data)
{
children.put(key, data);
}
public TreeItem getChild(String key)
{
return children.get(key);
}
public boolean hasChild(String key)
{
return children.containsKey(key);
}
@Override
public Iterator<TreeItem> iterator() {
return children.values().iterator();
}
}
/**
* This is our special case, root node. It is a TreeItem in itself
* but contains methods for building and retrieving items from our tree
*
*/
public static class TreeManager extends TreeItem
{
/**
* Will add an Item to the tree at the specified path with the value
* equal to the last item in the path, unless that Item already exists
*/
public void addData(List<String> path)
{
addData(this, path);
}
private void addData(TreeItem parent, List<String> path)
{
// if we're at the end of the path - create a node
String data = path.get(0);
if(path.size() == 1)
{
// unless there is already a node with this name
if(!parent.hasChild(data))
{
Group group = new Group();
group.setName(data);
parent.addChild(data, group);
}
}
else
{
// pass the tail of this path down to the next level in the hierarchy
addData(parent.getChild(data), path.subList(1, path.size()));
}
}
public Group getData(String[] path)
{
return (Group) getData(this, Arrays.asList(path));
}
public Group getData(List<String> path)
{
return (Group) getData(this, path);
}
private TreeItem getData(TreeItem parent, List<String> path)
{
if(parent == null || path.size() == 0)
{
throw new IllegalArgumentException("Invalid path specified in getData, remainder: "
+ Arrays.toString(path.toArray()));
}
String data = path.get(0);
if(path.size() == 1)
{
return parent.getChild(data);
}
else
{
// pass the tail of this path down to the next level in the hierarchy
return getData(parent.getChild(data), path.subList(1, path.size()));
}
}
}
public static class Group extends TreeItem {
private Map<String, Object> properties;
public Object getValue(Object key) {
return properties.get(key);
}
public Object putValue(String key, Object value) {
return properties.put(key, value);
}
public Group () {
super();
properties = new HashMap<String, Object>();
}
}
}
这是我们的json
{
"children": {
"Toyota": {
"properties": {},
"children": {
"Hybrid": {
"properties": {},
"children": {
"Compact": {
"properties": {},
"children": {
"Prius": {
"properties": {},
"children": {},
"name": "Prius"
}
},
"name": "Compact"
}
},
"name": "Hybrid"
},
"Gas": {
"properties": {},
"children": {
"Compact": {
"properties": {},
"children": {
"Corolla": {
"properties": {
"MPG": 38
},
"children": {},
"name": "Corolla"
},
"Camry": {
"properties": {
"MPG": 28
},
"children": {},
"name": "Camry"
}
},
"name": "Compact"
}
},
"name": "Gas"
}
},
"name": "Toyota"
},
"Honda": {
"properties": {},
"children": {
"Gas": {
"properties": {},
"children": {
"Compact": {
"properties": {},
"children": {
"Civic": {
"properties": {},
"children": {},
"name": "Civic"
}
},
"name": "Compact"
}
},
"name": "Gas"
}
},
"name": "Honda"
}
}
}
这是我的html文件...
<meta charset="utf-8">
.node circle {
cursor: pointer;
stroke: #3182bd;
stroke-width: 1.5px;
}
.node text {
font: 10px sans-serif;
pointer-events: none;
text-anchor: middle;
}
line.link {
fill: none;
stroke: #9ecae1;
stroke-width: 1.5px;
}
<script type="text/javascript" src="d3/d3.v3.min.js"></script>
<script>
var width = 960,
height = 500,
root;
var force = d3.layout.force()
.linkDistance(80)
.charge(-120)
.gravity(.04)
.size([width, height])
.on("tick", tick);
//adding as svg element
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var link = svg.selectAll(".link"),
node = svg.selectAll(".node");
d3.json("graph.json", function(error, json) {
root = json;
update(); //responsible for creating the layout
});
function update() {
var nodes = flatten(root),
/*
*d3.layout.tree() is the starting point
*for tree layouts in D3.
*The call to this function returns an object
* that contains a bunch of methods to configure
* the layout and also provides methods to
* compute the layout
**/
links = d3.layout.tree().links(nodes);//attach the nodes
// Restart the force layout.
force
.nodes(nodes)
.links(links)
.start();
// Update links.
link = link.data(links, function(d) { return d.target.id; });
link.exit().remove();
link.enter().insert("line", ".node")
.attr("class", "link");
// Update nodes.
node = node.data(nodes, function(d) { return d.id; });
node.exit().remove();
var nodeEnter = node.enter().append("g")
.attr("class", "node")
.on("click", click)
.call(force.drag);
nodeEnter.append("circle")
.attr("r", function(d) { return Math.sqrt(d.size) / 10 || 4.5; });
nodeEnter.append("text")
.attr("dy", ".35em")
.text(function(d) { return d.name; });
node.select("circle")
.style("fill", color);
}
/*Giving elements on click*/
function tick() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
}
/*Adjusting the color of each node*/
function color(d) {
return d._children ? "#3182bd" // collapsed package
: d.children ? "#c6dbef" // expanded package
: "#fd8d3c"; // leaf node
}
// Toggle children on click.
function click(d) {
if (d3.event.defaultPrevented) return; // ignore drag
if (d.children) {
d._children = d.children;
d.children = null;
} else {
d.children = d._children;
d._children = null;
}
update();
}
// Returns a list of all nodes under the root.
function flatten(root) {
var nodes = [], i = 0;
function recurse(node) {
if (node.children) node.children.forEach(recurse);
if (!node.id) node.id = ++i;
nodes.push(node);
}
recurse(root);
return nodes;
}
</script>
这是 json 和 html 文件，现在我必须动态地制作 json 并将响应设置回 D3 api。请帮助...