Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $

今天開發Android應用程序是用到了google的Gson這個jar包，主要是解析json的，解析一個json是一直在報錯錯誤信息如下：

java.util.concurrent.ExecutionException: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $

 

原因：解析後的結果和你返回賦值的對象不一致導致的。

 

舉例：

[{
	"Desc": "5201",
	"GrpList": ["5402", "53331314153"],
	"keep3": "2018121615234026942694100",
	"UserName": "5201",
	"UserTelno": "5201",
	"UserType": 1027
}, {
	"Desc": "5202",
	"GrpList": ["5402", "53331314153"],
	"keep3": "2018121615234026942694100",
	"UserName": "5202",
	"UserTelno": "5202",
	"UserType": 1027
}
]

以上json解析後肯定會返回一個ArrayList，我在代碼裏返回一個對象所以報錯了。

我剛開始寫的代碼：

ContactUser contactUser = contactGson.fromJson(reader, ContactUser.class);

正確的寫法如下： 

 

List<ContactUser> contactList = contactGson.fromJson(reader,new TypeToken<List<ContactUser>>() {}.getType());

 出現以上錯誤要確定具體的json字符串內容跟你解析後返回的類型是否對上。