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array_to_map_cn
Shaojin Wen edited this page Jul 15, 2024
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当我们的输入JSON是一个数组,但字段类型是Map,如下的场景:
{
"functions":[
{"name": "concat", "category": ["Array","String"]},
{"name": "count", "category": "aggregate"},
{"name": "count", "category": "window"}
]
}
希望反序列化的Java对象结构如下:
public static class Bean3 {
public final Map<String, Function> functions = new LinkedHashMap<>();
}
public static class Function {
public String name;
public final Set<Category> category = new LinkedHashSet<>();
}
public enum Category {
Array,
Aggregate,
Window,
Numeric,
String,
Datetime
}
}
FASTJSON2在2.0.52版本之后,提供了一个快捷的配置方式,能简化处理代码,如下:
public static class Bean3 {
// 这里配置需要,当反序列化输入JSONArray时,会用JSONArray中的每个元素的Key当做Map的Key来构造Map
@JSONField(arrayToMapKey = "name")
public final Map<String, Function> functions = new LinkedHashMap<>();
}
当需要处理重复时,则可以这样
public static class Bean3 {
// arrayToMapDuplicateHandler配置重复处理器,需要是BiConsumer的派生类
@JSONField(arrayToMapKey = "name", arrayToMapDuplicateHandler = FunctionDuplicateHandler.class)
public final Map<String, Function> functions = new LinkedHashMap<>();
}
static class FunctionDuplicateHandler
implements BiConsumer<Function, Function> {
@Override
public void accept(Function origin, Function newItem) {
origin.category.addAll(newItem.category);
}
}