Question

下面的代码导致图表没有绘制数据系列，正在加载的实际数据

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

Java ..

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从servlet发送Vector<Dataset>到javascript，使用response.getWriter().write(new Gson().toJson(datasets));

序列化数据

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}
    ]}
]

Answer 1

获得正确的格式，对于图表中的每个系列，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入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");
        }
    });
}

flot不显示gson数据

1 个答案: