我想使用杰克逊将 ArrayList 转换为 JsonArray。
Event.java:这是具有两个字段“field1”、“field2”的 java bean 类,映射为 JsonProperty。
我的目标是:
转变
ArrayList<Event> list = new ArrayList<Event>();
list.add(new Event("a1","a2"));
list.add(new Event("b1","b2"));
到
[
{"field1":"a1", "field":"a2"},
{"field1":"b1", "field":"b2"}
]
我能想到的方法是: writeListToJsonArray():
public void writeListToJsonArray() throws IOException {
ArrayList<Event> list = new ArrayList<Event>();
list.add(new Event("a1","a2"));
list.add(new Event("b1","b2"));
OutputStream out = new ByteArrayOutputStream();
JsonFactory jfactory = new JsonFactory();
JsonGenerator jGenerator = jfactory.createJsonGenerator(out, JsonEncoding.UTF8);
ObjectMapper mapper = new ObjectMapper();
jGenerator.writeStartArray(); // [
for (Event event : list) {
String e = mapper.writeValueAsString(event);
jGenerator.writeRaw(usage);
// here, big hassles to write a comma to separate json objects, when the last object in the list is reached, no comma
}
jGenerator.writeEndArray(); // ]
jGenerator.close();
System.out.println(out.toString());
}
我正在寻找类似的东西:
generator.write(out, list)
这直接将列表转换为json数组格式,然后将其写入输出流“out”。
更贪婪:
generator.write(out, list1)
generator.write(out, list2)
这只会将 list1、list2 转换/添加为单个 json 数组。然后将其写入“out”