flot 不显示 gson 数据

flot not displaying gson data

本文关键字：数据 gson 显示 flot      更新时间：2023-09-26

下面的代码导致图形没有绘制数据系列，正在加载的实际数据

rob@workLaptop:~$ cat /path/to/files/data/myFile.txt 
1,1
2,1
3,1

爪哇岛。。

import java.util.Vector;
    public class Dataset {
    private String name;
    private Vector<GraphPoint> points;
    public Dataset(String nameTemp){
        this.name = nameTemp;
        this.points = new Vector<GraphPoint>();
    }
}
使用

AJAX 将Vector<Dataset>从 servlet 发送到 javascript，数据使用 response.getWriter().write(new Gson().toJson(datasets)); 进行序列化

JavaScript ..

$(".body").append('<div id="content"><div class="demo-container"><div id="placeholder" class="demo-placeholder"></div></div></div>');
var datasets = JSON.parse(xmlhttp.responseText);
//alert(xmlhttp.responseText);          
var plotarea = $("#placeholder");
$.plot(plotarea, [datasets[0].points, datasets[1].points]);

alert(xmlhttp.responseText);输出..

[
    {"name":"myFile.txt",
    "points":[
        {"timestamp":30,"value":100},
        {"timestamp":31,"value":101},
        {"timestamp":32,"value":110}
    ]},
    {"name":"anotherFile.txt",
    "points":[
        {"timestamp":1382987630,"value":200},
        {"timestamp":1382987631,"value":201},
        {"timestamp":1382987632,"value":205}
    ]}
]

获得正确的格式，对于图形中的每个系列创建Dataset对象

public class Dataset {
    private String name;
    private Vector<Vector<Integer>> points;

将每个文件中的系列数据读取到Vector<Dataset> 

File[] files = finder("/path/to/files/" + request.getParameter("data") + "/");
    Vector<Dataset> datasets = new Vector<Dataset>();
    for (int i = 0; i < files.length; i++){
        datasets.add(readData(files[i]));
    }

将 JSON 数据发送到客户端

response.setContentType("application/json");
response.getWriter().write(new Gson().toJson(datasets));
System.out.println(new Gson().toJson(datasets));

系统输出..

[{"name":"myFile.txt","points":[[1,1],[2,1],[3,1]]},{"name":"anotherFile.txt","points":[[0,10],[2,20],[5,50]]}] 

private Dataset readData(File file){
    Dataset dataset = new Dataset(file.getName());
    try{
        FileInputStream fstream = new FileInputStream(file);
        DataInputStream in = new DataInputStream(fstream);
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        String strLine;
        while ((strLine = br.readLine()) != null){
            Vector<Integer> points = new Vector<Integer>();
            points.add(Integer.parseInt(strLine.split(",")[0]));
            points.add(Integer.parseInt(strLine.split(",")[1]));
            dataset.addset(points);
        }
        in.close();
    }catch (Exception e) {
        e.printStackTrace();
    }
    return dataset;
}
private File[] finder(String dirName) {
    File dir = new File(dirName);
    return dir.listFiles(new FilenameFilter() {
        public boolean accept(File dir, String filename) {
            return filename.endsWith(".txt");
        }
    });
}
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