java.lang.OutOfMemoryError:尝试将Java Object转换为Json String时的Java堆空间

Question

我尝试将csv文件转换为对象代表csv中的1行的对象的Json文件200K.

我在32位和Project配置VM参数上安装了Java: -Xmx1024m

但是我得到:

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Unknown Source)
    at java.lang.AbstractStringBuilder.expandCapacity(Unknown Source)
    at java.lang.AbstractStringBuilder.ensureCapacityInternal(Unknown Source)
    at java.lang.AbstractStringBuilder.append(Unknown Source)
    at java.lang.StringBuffer.append(Unknown Source)
    at java.io.StringWriter.write(Unknown Source)
    at com.google.gson.stream.JsonWriter.string(JsonWriter.java:478)
    at com.google.gson.stream.JsonWriter.value(JsonWriter.java:328)
    at com.google.gson.Streams.write(Streams.java:113)
    at com.google.gson.Streams.write(Streams.java:136)
    at com.google.gson.Streams.write(Streams.java:136)
    at com.google.gson.Streams.write(Streams.java:124)
    at com.google.gson.Streams.write(Streams.java:136)
    at com.google.gson.Gson.toJson(Gson.java:362)
    at com.google.gson.Gson.toJson(Gson.java:346)
    at com.google.gson.Gson.toJson(Gson.java:260)
    at com.google.gson.Gson.toJson(Gson.java:240)
    at ConvertFromCsv2JsonTWC.init(ConvertFromCsv2JsonTWC.java:186)
    at ConvertFromCsv2JsonTWC.main(ConvertFromCsv2JsonTWC.java:48)

在排队:

Gson gson = new Gson();

String output = gson.toJson(container);// <---- crash

对于50k行,它工作正常.

这是Json I构建的模板:

{
    "crs": {
        "type": "none"
    },
    "type": "FeatureCollection",
    "features": [{
        "geometry": {
            "type": "Point"
        },
        "properties": {
            "ap mac": "00:11:22:33:44:55",
            "ssid": "WiFi",
            "lat": "35.111111",
            "long": "-118.11111",
            "address": "370 xxxxxx",
            "city": "xxxxxxx",
            "state": "CA",
            "zip code": "11111",
            "country": "US",
            "business n": "",
            "location c": "Health Club/Gym",
            "location q": "",
            "indoor fla": "yes"
        },
        "point": [35.390284,
        -118.9929],
        "id": 0,
        "type": "Feature"
    },
          {...},
          ... 
          200000...

所以我在properties列表中有200K对象

解决方法是创建每个20k的单独文件,但这不是好方法.

我怎么解决这个问题？

谢谢,

Answer 1

我建议您使用流式传输，而不是尝试将其全部复制到String.