前端-collapsibleTree-前端--易笔记-weiyer.com

　　核心提示：本文要用到的一个非常牛逼的插件 d3.js 数据可视化插件。下面开始我们要干的事：1.写一个静态的collapsibleTree。从Mike大神那里抄一段代码过来：1.1 首先引入js包：script...

本文要用到的一个非常牛逼的插件 d3.js 数据可视化插件。

下面开始我们要干的事：

1.写一个静态的collapsibleTree。从Mike大神那里抄一段代码过来：

1.1 首先引入js包：

<script src="${pageContext.request.contextPath}/static/js/jquery.min.js"></script>
	<script src="${pageContext.request.contextPath}/static/js/d3.min.js"></script>

1.2 在页面加入样式

1.3添加 flare.json 文件：

{
 "name": "flare",
 "children": [
  {
   "name": "analytics",
   "children": [
    {
     "name": "cluster",
     "children": [
      {"name": "AgglomerativeCluster", "size": 3938},
      {"name": "CommunityStructure", "size": 3812},
      {"name": "HierarchicalCluster", "size": 6714},
      {"name": "MergeEdge", "size": 743}
     ]
    },
    {
     "name": "graph",
     "children": [
      {"name": "BetweennessCentrality", "size": 3534},
      {"name": "LinkDistance", "size": 5731},
      {"name": "MaxFlowMinCut", "size": 7840},
      {"name": "ShortestPaths", "size": 5914},
      {"name": "SpanningTree", "size": 3416}
     ]
    },
    {
     "name": "optimization",
     "children": [
      {"name": "AspectRatioBanker", "size": 7074}
     ]
    }
   ]
  },
  {
   "name": "animate",
   "children": [
    {"name": "Easing", "size": 17010},
    {"name": "FunctionSequence", "size": 5842},
    {
     "name": "interpolate",
     "children": [
      {"name": "ArrayInterpolator", "size": 1983},
      {"name": "ColorInterpolator", "size": 2047},
      {"name": "DateInterpolator", "size": 1375},
      {"name": "Interpolator", "size": 8746},
      {"name": "MatrixInterpolator", "size": 2202},
      {"name": "NumberInterpolator", "size": 1382},
      {"name": "ObjectInterpolator", "size": 1629},
      {"name": "PointInterpolator", "size": 1675},
      {"name": "RectangleInterpolator", "size": 2042}
     ]
    },
    {"name": "ISchedulable", "size": 1041},
    {"name": "Parallel", "size": 5176},
    {"name": "Pause", "size": 449},
    {"name": "Scheduler", "size": 5593},
    {"name": "Sequence", "size": 5534},
    {"name": "Transition", "size": 9201},
    {"name": "Transitioner", "size": 19975},
    {"name": "TransitionEvent", "size": 1116},
    {"name": "Tween", "size": 6006}
   ]
  },
  {
   "name": "data",
   "children": [
    {
     "name": "converters",
     "children": [
      {"name": "Converters", "size": 721},
      {"name": "DelimitedTextConverter", "size": 4294},
      {"name": "GraphMLConverter", "size": 9800},
      {"name": "IDataConverter", "size": 1314},
      {"name": "JSONConverter", "size": 2220}
     ]
    },
    {"name": "DataField", "size": 1759},
    {"name": "DataSchema", "size": 2165},
    {"name": "DataSet", "size": 586},
    {"name": "DataSource", "size": 3331},
    {"name": "DataTable", "size": 772},
    {"name": "DataUtil", "size": 3322}
   ]
  },
  {
   "name": "display",
   "children": [
    {"name": "DirtySprite", "size": 8833},
    {"name": "LineSprite", "size": 1732},
    {"name": "RectSprite", "size": 3623},
    {"name": "TextSprite", "size": 10066}
   ]
  },
  {
   "name": "flex",
   "children": [
    {"name": "FlareVis", "size": 4116}
   ]
  },
  {
   "name": "physics",
   "children": [
    {"name": "DragForce", "size": 1082},
    {"name": "GravityForce", "size": 1336},
    {"name": "IForce", "size": 319},
    {"name": "NBodyForce", "size": 10498},
    {"name": "Particle", "size": 2822},
    {"name": "Simulation", "size": 9983},
    {"name": "Spring", "size": 2213},
    {"name": "SpringForce", "size": 1681}
   ]
  },
  {
   "name": "query",
   "children": [
    {"name": "AggregateExpression", "size": 1616},
    {"name": "And", "size": 1027},
    {"name": "Arithmetic", "size": 3891},
    {"name": "Average", "size": 891},
    {"name": "BinaryExpression", "size": 2893},
    {"name": "Comparison", "size": 5103},
    {"name": "CompositeExpression", "size": 3677},
    {"name": "Count", "size": 781},
    {"name": "DateUtil", "size": 4141},
    {"name": "Distinct", "size": 933},
    {"name": "Expression", "size": 5130},
    {"name": "ExpressionIterator", "size": 3617},
    {"name": "Fn", "size": 3240},
    {"name": "If", "size": 2732},
    {"name": "IsA", "size": 2039},
    {"name": "Literal", "size": 1214},
    {"name": "Match", "size": 3748},
    {"name": "Maximum", "size": 843},
    {
     "name": "methods",
     "children": [
      {"name": "add", "size": 593},
      {"name": "and", "size": 330},
      {"name": "average", "size": 287},
      {"name": "count", "size": 277},
      {"name": "distinct", "size": 292},
      {"name": "p", "size": 595},
      {"name": "eq", "size": 594},
      {"name": "fn", "size": 460},
      {"name": "gt", "size": 603},
      {"name": "gte", "size": 625},
      {"name": "iff", "size": 748},
      {"name": "isa", "size": 461},
      {"name": "lt", "size": 597},
      {"name": "lte", "size": 619},
      {"name": "max", "size": 283},
      {"name": "min", "size": 283},
      {"name": "mod", "size": 591},
      {"name": "mul", "size": 603},
      {"name": "neq", "size": 599},
      {"name": "not", "size": 386},
      {"name": "or", "size": 323},
      {"name": "orderby", "size": 307},
      {"name": "range", "size": 772},
      {"name": "select", "size": 296},
      {"name": "stddev", "size": 363},
      {"name": "sub", "size": 600},
      {"name": "sum", "size": 280},
      {"name": "update", "size": 307},
      {"name": "variance", "size": 335},
      {"name": "where", "size": 299},
      {"name": "xor", "size": 354},
      {"name": "_", "size": 264}
     ]
    },
    {"name": "Minimum", "size": 843},
    {"name": "Not", "size": 1554},
    {"name": "Or", "size": 970},
    {"name": "Query", "size": 13896},
    {"name": "Range", "size": 1594},
    {"name": "StringUtil", "size": 4130},
    {"name": "Sum", "size": 791},
    {"name": "Variable", "size": 1124},
    {"name": "Variance", "size": 1876},
    {"name": "Xor", "size": 1101}
   ]
  },
  {
   "name": "scale",
   "children": [
    {"name": "IScaleMap", "size": 2105},
    {"name": "LinearScale", "size": 1316},
    {"name": "LogScale", "size": 3151},
    {"name": "OrdinalScale", "size": 3770},
    {"name": "QuantileScale", "size": 2435},
    {"name": "QuantitativeScale", "size": 4839},
    {"name": "RootScale", "size": 1756},
    {"name": "Scale", "size": 4268},
    {"name": "ScaleType", "size": 1821},
    {"name": "TimeScale", "size": 5833}
   ]
  },
  {
   "name": "util",
   "children": [
    {"name": "Arrays", "size": 8258},
    {"name": "Colors", "size": 10001},
    {"name": "Dates", "size": 8217},
    {"name": "Displays", "size": 12555},
    {"name": "Filter", "size": 2324},
    {"name": "Geometry", "size": 10993},
    {
     "name": "heap",
     "children": [
      {"name": "FibonacciHeap", "size": 9354},
      {"name": "HeapNode", "size": 1233}
     ]
    },
    {"name": "IEvaluable", "size": 335},
    {"name": "IPredicate", "size": 383},
    {"name": "IValueProxy", "size": 874},
    {
     "name": "math",
     "children": [
      {"name": "DenseMatrix", "size": 3165},
      {"name": "IMatrix", "size": 2815},
      {"name": "SparseMatrix", "size": 3366}
     ]
    },
    {"name": "Maths", "size": 17705},
    {"name": "Orientation", "size": 1486},
    {
     "name": "palette",
     "children": [
      {"name": "ColorPalette", "size": 6367},
      {"name": "Palette", "size": 1229},
      {"name": "ShapePalette", "size": 2059},
      {"name": "SizePalette", "size": 2291}
     ]
    },
    {"name": "Property", "size": 5559},
    {"name": "Shapes", "size": 19118},
    {"name": "Sort", "size": 6887},
    {"name": "Stats", "size": 6557},
    {"name": "Strings", "size": 22026}
   ]
  },
  {
   "name": "vis",
   "children": [
    {
     "name": "axis",
     "children": [
      {"name": "Axes", "size": 1302},
      {"name": "Axis", "size": 24593},
      {"name": "AxisGridLine", "size": 652},
      {"name": "AxisLabel", "size": 636},
      {"name": "CartesianAxes", "size": 6703}
     ]
    },
    {
     "name": "controls",
     "children": [
      {"name": "AnchorControl", "size": 2138},
      {"name": "ClickControl", "size": 3824},
      {"name": "Control", "size": 1353},
      {"name": "ControlList", "size": 4665},
      {"name": "DragControl", "size": 2649},
      {"name": "ExpandControl", "size": 2832},
      {"name": "HoverControl", "size": 4896},
      {"name": "IControl", "size": 763},
      {"name": "PanZoomControl", "size": 5222},
      {"name": "SelectionControl", "size": 7862},
      {"name": "TooltipControl", "size": 8435}
     ]
    },
    {
     "name": "data",
     "children": [
      {"name": "Data", "size": 20544},
      {"name": "DataList", "size": 19788},
      {"name": "DataSprite", "size": 10349},
      {"name": "EdgeSprite", "size": 3301},
      {"name": "NodeSprite", "size": 19382},
      {
       "name": "render",
       "children": [
        {"name": "ArrowType", "size": 698},
        {"name": "EdgeRenderer", "size": 5569},
        {"name": "IRenderer", "size": 353},
        {"name": "ShapeRenderer", "size": 2247}
       ]
      },
      {"name": "ScaleBinding", "size": 11275},
      {"name": "Tree", "size": 7147},
      {"name": "TreeBuilder", "size": 9930}
     ]
    },
    {
     "name": "events",
     "children": [
      {"name": "DataEvent", "size": 2313},
      {"name": "SelectionEvent", "size": 1880},
      {"name": "TooltipEvent", "size": 1701},
      {"name": "VisualizationEvent", "size": 1117}
     ]
    },
    {
     "name": "legend",
     "children": [
      {"name": "Legend", "size": 20859},
      {"name": "LegendItem", "size": 4614},
      {"name": "LegendRange", "size": 10530}
     ]
    },
    {
     "name": "operator",
     "children": [
      {
       "name": "distortion",
       "children": [
        {"name": "BifocalDistortion", "size": 4461},
        {"name": "Distortion", "size": 6314},
        {"name": "FisheyeDistortion", "size": 3444}
       ]
      },
      {
       "name": "encoder",
       "children": [
        {"name": "ColorEncoder", "size": 3179},
        {"name": "Encoder", "size": 4060},
        {"name": "PropertyEncoder", "size": 4138},
        {"name": "ShapeEncoder", "size": 1690},
        {"name": "SizeEncoder", "size": 1830}
       ]
      },
      {
       "name": "filter",
       "children": [
        {"name": "FisheyeTreeFilter", "size": 5219},
        {"name": "GraphDistanceFilter", "size": 3165},
        {"name": "VisibilityFilter", "size": 3509}
       ]
      },
      {"name": "IOperator", "size": 1286},
      {
       "name": "label",
       "children": [
        {"name": "Labeler", "size": 9956},
        {"name": "RadialLabeler", "size": 3899},
        {"name": "StackedAreaLabeler", "size": 3202}
       ]
      },
      {
       "name": "layout",
       "children": [
        {"name": "AxisLayout", "size": 6725},
        {"name": "BundledEdgeRouter", "size": 3727},
        {"name": "CircleLayout", "size": 9317},
        {"name": "CirclePackingLayout", "size": 12003},
        {"name": "DendrogramLayout", "size": 4853},
        {"name": "ForceDirectedLayout", "size": 8411},
        {"name": "IcicleTreeLayout", "size": 4864},
        {"name": "IndentedTreeLayout", "size": 3174},
        {"name": "Layout", "size": 7881},
        {"name": "NodeLinkTreeLayout", "size": 12870},
        {"name": "PieLayout", "size": 2728},
        {"name": "RadialTreeLayout", "size": 12348},
        {"name": "RandomLayout", "size": 870},
        {"name": "StackedAreaLayout", "size": 9121},
        {"name": "TreeMapLayout", "size": 9191}
       ]
      },
      {"name": "Operator", "size": 2490},
      {"name": "OperatorList", "size": 5248},
      {"name": "OperatorSequence", "size": 4190},
      {"name": "OperatorSwitch", "size": 2581},
      {"name": "SortOperator", "size": 2023}
     ]
    },
    {"name": "Visualization", "size": 16540}
   ]
  }
 ]
}

1.4 加入js文件

function startIni(){
var margin = {top: 20, right: 120, bottom: 20, left: 120},
    width = 960 - margin.right - margin.left,
    height = 800 - margin.top - margin.bottom;

var i = 0,
    duration = 750,
    root;

var tree = d3.layout.tree()
    .size([height, width]);

var diagonal = d3.svg.diagonal()
    .projection(function(d) { return [d.y, d.x]; });

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.right + margin.left)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.json("static/json/flare.json", function(error, flare) {
  if (error) throw error;

  root = flare;
  root.x0 = height / 2;
  root.y0 = 0;

  function collapse(d) {
    if (d.children) {
      d._children = d.children;
      d._children.forEach(collapse);
      d.children = null;
    }
  }

  root.children.forEach(collapse);
  update(root);
});

d3.select(self.frameElement).style("height", "800px");

function update(source) {

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse(),
      links = tree.links(nodes);

  // Normalize for fixed-depth.
  nodes.forEach(function(d) { d.y = d.depth * 180; });

  // Update the nodes…
  var node = svg.selectAll("g.node")
      .data(nodes, function(d) { return d.id || (d.id = ++i); });

  // Enter any new nodes at the parent's previous position.
  var nodeEnter = node.enter().append("g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
      .on("click", click);

  nodeEnter.append("circle")
      .attr("r", 1e-6)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeEnter.append("text")
      .attr("x", function(d) { return d.children || d._children ? -10 : 10; })
      .attr("dy", ".35em")
      .attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
      .text(function(d) { return d.name; })
      .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.
  var nodeUpdate = node.transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

  nodeUpdate.select("circle")
      .attr("r", 4.5)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeUpdate.select("text")
      .style("fill-opacity", 1);

  // Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .remove();

  nodeExit.select("circle")
      .attr("r", 1e-6);

  nodeExit.select("text")
      .style("fill-opacity", 1e-6);

  // Update the links…
  var link = svg.selectAll("path.link")
      .data(links, function(d) { return d.target.id; });

  // Enter any new links at the parent's previous position.
  link.enter().insert("path", "g")
      .attr("class", "link")
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      });

  // Transition links to their new position.
  link.transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition exiting nodes to the parent's new position.
  link.exit().transition()
      .duration(duration)
      .attr("d", function(d) {
        var o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      })
      .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children on click.
function click(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update(d);
}

}

startIni();

1.5 运行项目，得到如下图所示效果图

前端-collapsibleTree

从上面可以看出当你展开多层的时候文字显示就会出现相叠的情况，这个应该是可以修改的吧，参考国内这位大神的文章不知道有没有帮助：https://blog.csdn.net/tianxuzhang/article/details/14170243

2. 动态加载

由上面的js 我们可以知道它是读取了flare.json文件，然后把它可视化。

但是从d3.json("static/json/flare.json", function(error, flare) {})这一句可以看出它要的是json文件，不能发送一个请求到后台，所以我的做法是在渲染页面之前发一个请求给后台，得到跟flare.json格式（name，children）相似的json字符串，然后把它覆盖到flare.json文件。这样它读到的json数据就是你的后台数据。

2.1 把上面的js 换成如下：

	<script type="text/javascript">
$.ajax({
	type: "POST",
	url: "country/collapsibleTree",
	//async: false,
	dataType: "json",
	success: function(data){
		console.info(data);
		startIni();
	}
});

	
function startIni(){
var margin = {top: 20, right: 120, bottom: 20, left: 120},
    width = 960 - margin.right - margin.left,
    height = 800 - margin.top - margin.bottom;

var i = 0,
    duration = 750,
    root;

var tree = d3.layout.tree()
    .size([height, width]);

var diagonal = d3.svg.diagonal()
    .projection(function(d) { return [d.y, d.x]; });

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.right + margin.left)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.json("static/json/flare.json", function(error, flare) {
  if (error) throw error;

  root = flare;
  root.x0 = height / 2;
  root.y0 = 0;

  function collapse(d) {
    if (d.children) {
      d._children = d.children;
      d._children.forEach(collapse);
      d.children = null;
    }
  }

  root.children.forEach(collapse);
  update(root);
});

d3.select(self.frameElement).style("height", "800px");

function update(source) {

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse(),
      links = tree.links(nodes);

  // Normalize for fixed-depth.
  nodes.forEach(function(d) { d.y = d.depth * 180; });

  // Update the nodes…
  var node = svg.selectAll("g.node")
      .data(nodes, function(d) { return d.id || (d.id = ++i); });

  // Enter any new nodes at the parent's previous position.
  var nodeEnter = node.enter().append("g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
      .on("click", click);

  nodeEnter.append("circle")
      .attr("r", 1e-6)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeEnter.append("text")
      .attr("x", function(d) { return d.children || d._children ? -10 : 10; })
      .attr("dy", ".35em")
      .attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
      .text(function(d) { return d.name; })
      .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.
  var nodeUpdate = node.transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

  nodeUpdate.select("circle")
      .attr("r", 4.5)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeUpdate.select("text")
      .style("fill-opacity", 1);

  // Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .remove();

  nodeExit.select("circle")
      .attr("r", 1e-6);

  nodeExit.select("text")
      .style("fill-opacity", 1e-6);

  // Update the links…
  var link = svg.selectAll("path.link")
      .data(links, function(d) { return d.target.id; });

  // Enter any new links at the parent's previous position.
  link.enter().insert("path", "g")
      .attr("class", "link")
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      });

  // Transition links to their new position.
  link.transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition exiting nodes to the parent's new position.
  link.exit().transition()
      .duration(duration)
      .attr("d", function(d) {
        var o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      })
      .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children on click.
function click(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update(d);
}
}

</script>

2.2 oracle数据库脚本沿用了上一次博客的脚本：https://blog.csdn.net/apathecrazyfan/article/details/77783111

2.3 后台Controller类主要方法为：

/**
	 * 
	 * @return
	 */
	@RequestMapping(value = "/collapsibleTree", method = RequestMethod.POST)
	@ResponseBody
	public Map collapsibleTree(){
		Random rd = new Random();
		Map map = new HashMap();
		List countrys = new ArrayList();
		countrys = countryService.getAllCountryWithDetail();
		map.put("name", "country");
		map.put("children", countrys);
		String filePath = servletContext.getRealPath("static/json/flare.json");
		System.out.println("before clear ==>");
		readFileByLines(filePath);
		//清空flare.json
		clearFile(filePath);
		//System.out.println("after clear ==>");

		Gson gson = new Gson();
		String jsonString = gson.toJson(map);
		System.out.println( jsonString);
		jsonString = jsonString.replaceAll("countryCode", "name");
		jsonString = jsonString.replaceAll("provinceCode", "name");
		jsonString = jsonString.replaceAll("cityCode", "name");
		
		jsonString = jsonString.replaceAll("provinces", "children");
		jsonString = jsonString.replaceAll("cities", "children");
		
		jsonString = jsonString.replaceAll("countryId", "size");
		jsonString = jsonString.replaceAll("provinceId", "size");
		jsonString = jsonString.replaceAll("cityId", "size");
		jsonString = jsonString.replaceAll("\\d", rd.nextInt(100)+"");
		System.out.println( jsonString);
		//写入flare.json
		writeFileByLines(filePath, jsonString);
		//System.out.println("after write ==>");
		readFileByLines(filePath);
		//System.out.println( "jsonString ==>" + jsonString);
		
		return map;
	}

	/**
	 * 以行为单位读取文件，常用于读面向行的格式化文件
	 */
	private static void readFileByLines(String fileName) {
		File file = new File(fileName);
		BufferedReader reader = null;
		try {
			System.out.println("以行为单位读取文件内容，一次读一整行：");
			reader = new BufferedReader(new FileReader(file));
			String tempString = null;
			int line = 1;
			// 一次读入一行，直到读入null为文件结束
			while ((tempString = reader.readLine()) != null) {
				// 显示行号
				System.out.println("line " + line + ": " + tempString);
				line++;
			}
			reader.close();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (reader != null) {
				try {
					reader.close();
				} catch (IOException e1) {
				}
			}
		}
	}

	/**
	 * 清空文件
	 */
	private static void clearFile(String fileName) { 
		File file = new File(fileName);
		BufferedWriter br = null;
		try {
			if(file.exists()){
				br = new BufferedWriter(new FileWriter(fileName));
				br.write("");
				br.flush();
				br.close();
			}else{
				return;
			} 
		}catch (IOException e) {
			e.printStackTrace();
			return;
		} finally{
			if( br != null){
				try {
					br.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}


	/**
	 * 写文件
	 */
	private static void writeFileByLines(String fileName, String appendString) { 
		File file = new File(fileName);
		BufferedWriter br = null;
		try {
			if(!file.exists()){
				file.createNewFile();
			}
			
			br = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), "UTF-8"));
			br.write(appendString);
			br.flush();
			br.close();
		} catch (IOException e) {
			e.printStackTrace();
		} finally{
			if(br != null){
				try {
					br.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}

2.4 效果图如下：

前端-collapsibleTree

当然细心的同志会发现有时候结果并不是显示从数据库得到的数据，而是原先flare.json的数据或者没有数据显示，也就是静态显示的数据，这种情况都是write操作造成了，因为写操作是要时间。它可以还没写，所以这时就是原先flare.json的数据；可以是把flare.json数据清空，还没来得及写前端就渲染了，所以这时是空的，什么也不显示。

当然厉害的同志可以不像我这样操作，没必要把写后台得到的数据写入flare.json，再js渲染它，可以直接就渲染后台得到的数据。

还有一个就是乱码的情况。确保存在数据库的数据是好的（不乱码），那么乱码只可能出现在写操作上了。

前端-collapsibleTree

时间：2017/9/5 10:03:00 点击：

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