B4J代码本地运行正常，部署到服务器报JSON Object expected错误

问题场景 #

本地运行B4J代码完全正常，但部署到服务器后触发java.lang.RuntimeException: java.lang.RuntimeException: JSON Object expected异常。本地环境可正常读取并处理endpoints.json文件，服务器环境下却触发该异常。

相关代码 #

JSON读取处理代码 #

Sub tickInterval_tick
    time.Enabled = False
    Dim endpointList As List
    Dim endpointMap As Map
    endpointList = File.ReadList(File.DirApp, "endpoints.json")
    Dim filePath As String = File.Combine(File.DirApp, "endpoints.json")
    Log("File path: " & filePath)
    Dim parser As JSONParser
    endpointMap.Initialize
    parser.Initialize(endpointList.Get(0))
    Dim endpointArray As List = parser.NextArray
    For t = 0 To endpointArray.Size - 1
        endpointMap = endpointArray.Get(t)
        ContainerReady(endpointMap.Get("name"), endpointMap.Get("host"), endpointMap.Get("token"))
    Next
    time.Enabled= True
End Sub

endpoints.json内容 #

[{"host":"https://xxxx:xxxx:xxxx","name":"OKD 1","token":"Bearer xxxxxxxxxx"}]

完整报错堆栈 #

java.lang.RuntimeException: java.lang.RuntimeException: JSON Object expected.
        at anywheresoftware.b4a.BA.raiseEvent2(BA.java:140)
        at anywheresoftware.b4a.BA$3.run(BA.java:267)
        at anywheresoftware.b4a.keywords.SimpleMessageLoop.runMessageLoop(SimpleMessageLoop.java:47)
        at anywheresoftware.b4a.StandardBA.startMessageLoop(StandardBA.java:43)
        at anywheresoftware.b4a.keywords.Common.StartMessageLoop(Common.java:180)
        at b4j.example.main._appstart(main.java:85)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:577)
        at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)
        at anywheresoftware.b4a.BA.raiseEvent(BA.java:98)
        at b4j.example.main.main(main.java:28)
Caused by: java.lang.RuntimeException: JSON Object expected.
        at anywheresoftware.b4j.objects.collections.JSONParser.NextObject(JSONParser.java:67)
        at b4j.example.main._shcurl_processcompleted(main.java:424)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
    at java.base/java.lang.reflect.Method.invoke(Method.java:577)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)

排查分析 #

1. 文件读取逻辑缺陷：当前用File.ReadList按行读取JSON文件，若服务器上的endpoints.json存在换行、空白行或编码差异，endpointList.Get(0)可能无法获取完整的JSON数组内容，导致解析失败。
2. 路径与权限问题：服务器上File.DirApp指向的目录可能不存在endpoints.json，或程序无文件读取权限，造成读取内容为空或错误。
3. 异常根源指向：注意到堆栈中异常实际来自_shcurl_processcompleted方法，而非tickInterval_tick的本地JSON读取——说明问题大概率出在ContainerReady调用的shcurl进程返回结果的解析环节：本地环境中shcurl返回正常JSON对象，但服务器上返回内容不符合预期（比如空响应、非JSON格式的错误页）。

解决方法 #

优化本地JSON文件读取 #

• 改用File.ReadString直接读取整个文件内容，避免按行读取的潜在问题：

Sub tickInterval_tick
    time.Enabled = False
    Dim endpointMap As Map
    Dim filePath As String = File.Combine(File.DirApp, "endpoints.json")
    Log("File path: " & filePath)
    ' 直接读取完整文件内容
    Dim jsonContent As String = File.ReadString(File.DirApp, "endpoints.json")
    Dim parser As JSONParser
    endpointMap.Initialize
    parser.Initialize(jsonContent)
    Dim endpointArray As List = parser.NextArray
    For t = 0 To endpointArray.Size - 1
        endpointMap = endpointArray.Get(t)
        ContainerReady(endpointMap.Get("name"), endpointMap.Get("host"), endpointMap.Get("token"))
    Next
    time.Enabled= True
End Sub

• 验证服务器文件状态：确认endpoints.json存在于File.DirApp指向的目录，且程序拥有读取权限；检查文件编码与本地一致（推荐UTF-8无BOM格式）。

排查shcurl_processcompleted环节 #

• 在该方法中添加日志，输出原始返回内容，确认是否为有效JSON对象：

Sub shcurl_processcompleted (Success As Boolean, ExitCode As Int, StdOut As String, StdErr As String)
    Log("shcurl stdout: " & StdOut)
    Log("shcurl stderr: " & StdErr)
    If Success And ExitCode = 0 Then
        ' 先校验返回内容有效性
        If StdOut.Trim.Length = 0 Then
            Log("shcurl返回内容为空")
            Return
        End If
        Try
            Dim parser As JSONParser
            parser.Initialize(StdOut)
            Dim resultMap As Map = parser.NextObject
            ' 后续业务逻辑
        Catch
            Log("解析shcurl返回JSON失败: " & LastException.Message)
        End Try
    Else
        Log("shcurl执行失败，错误码: " & ExitCode)
    End If
End Sub

• 检查服务器shcurl执行环境：确认目标接口可访问、请求参数正确，返回的是预期的JSON对象而非HTML错误页、空响应等非预期内容。

内容的提问来源于stack exchange，提问作者Ardean Angkasa