@Test
public void jsonTest() throws Exception {
    String text = "{\n" +
            "   "$":{\n" +
            "      "generated":"2021-08-30 15:50:21",\n" +
            "      "fitlerFrom":"2021-08-30 15:00:00",\n" +
            "      "fitlerTo":"2021-09-01 15:00:00"\n" +
            "   },\n" +
            "   "file":[\n" +
            "      {\n" +
            "         "$":{\n" +
            "            "type":"media",\n" +
            "            "id":"23",\n" +
            "            "size":"4832",\n" +
            "            "md5":"d59f5fc84ef7747f27baddc07fe81487",\n" +
            "            "path":"http://localhost/xmds.php?file=69ff812a81d936a1bf2ded27c286330e&displayId=3&type=M&itemId=23",\n" +
            "            "saveAs":"xibo-webpage-render.js",\n" +
            "            "download":"http"\n" +
            "         }\n" +
            "      },\n" +
            "      {\n" +
            "         "$":{\n" +
            "            "type":"media",\n" +
            "            "id":"6",\n" +
            "            "size":"160251",\n" +
            "            "md5":"67bb26c11dba6c366834e65f5933aff2",\n" +
            "            "path":"http://localhost/xmds.php?file=69ff812a81d936a1bf2ded27c286330e&displayId=3&type=M&itemId=6",\n" +
            "            "saveAs":"moment.js",\n" +
            "            "download":"http"\n" +
            "         }\n" +
            "      },\n" +
            "      {\n" +
            "         "$":{\n" +
            "            "type":"blacklist"\n" +
            "         }\n" +
            "      }\n" +
            "   ]\n" +
            "}";
    Gson gson = new Gson();
    FileWrapper wrapper = gson.fromJson(text, FileWrapper.class);
    System.out.println(wrapper);
}

public static class MetaData {
    @SerializedName("generated")
    @Expose
    private String generated;
    @SerializedName("fitlerFrom")
    @Expose
    private String fitlerFrom;
    @SerializedName("fitlerTo")
    @Expose
    private String fitlerTo;

    public String getGenerated() {
        return generated;
    }

    public void setGenerated(String generated) {
        this.generated = generated;
    }

    public String getFitlerFrom() {
        return fitlerFrom;
    }

    public void setFitlerFrom(String fitlerFrom) {
        this.fitlerFrom = fitlerFrom;
    }

    public String getFitlerTo() {
        return fitlerTo;
    }

    public void setFitlerTo(String fitlerTo) {
        this.fitlerTo = fitlerTo;
    }

    @Override
    public String toString() {
        return "MetaData{" +
                "generated='" + generated + ''' +
                ", fitlerFrom='" + fitlerFrom + ''' +
                ", fitlerTo='" + fitlerTo + ''' +
                '}';
    }
}
public static class FileItem {
    @SerializedName("type")
    @Expose
    private String type;
    @SerializedName("id")
    @Expose
    private String id;
    @SerializedName("size")
    @Expose
    private String size;
    @SerializedName("md5")
    @Expose
    private String md5;
    @SerializedName("path")
    @Expose
    private String path;
    @SerializedName("saveAs")
    @Expose
    private String saveAs;
    @SerializedName("download")
    @Expose
    private String download;

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getSize() {
        return size;
    }

    public void setSize(String size) {
        this.size = size;
    }

    public String getMd5() {
        return md5;
    }

    public void setMd5(String md5) {
        this.md5 = md5;
    }

    public String getPath() {
        return path;
    }

    public void setPath(String path) {
        this.path = path;
    }

    public String getSaveAs() {
        return saveAs;
    }

    public void setSaveAs(String saveAs) {
        this.saveAs = saveAs;
    }

    public String getDownload() {
        return download;
    }

    public void setDownload(String download) {
        this.download = download;
    }

    @Override
    public String toString() {
        return "FileItem{" +
                "type='" + type + ''' +
                ", id='" + id + ''' +
                ", size='" + size + ''' +
                ", md5='" + md5 + ''' +
                ", path='" + path + ''' +
                ", saveAs='" + saveAs + ''' +
                ", download='" + download + ''' +
                '}';
    }
}
public static class FileWrapper {

    @SerializedName("$")
    @Expose
    private MetaData metaData;
    @SerializedName("file")
    @Expose
    private List files = null;

    public MetaData getMetaData() {
        return metaData;
    }

    public void setMetaData(MetaData metaData) {
        this.metaData = metaData;
    }

    public List getFiles() {
        return files;
    }

    public void setFiles(List files) {
        this.files = files;
    }

    @Override
    public String toString() {
        return "FileWrapper{" +
                "metaData=" + metaData +
                ", files=" + files +
                '}';
    }
}

public static class File {

    @SerializedName("$")
    @Expose
    private FileItem item;

    public void setItem(FileItem item) {
        this.item = item;
    }

    public FileItem getItem() {
        return item;
    }

    @Override
    public String toString() {
        return "File{" +
                "item=" + item +
                '}';
    }
}
</pre>