Не может десериализации JSON для Pojo

Question

У меня есть JSON хранится в БДЕ, и я десериализацию его в POJO

JSON in DB

{ 
"requests": [ 
    { 
    "url": "http://localhost:8080/wst-server-1.0-SNAPSHOT/services/rest/", 
    "path": "3/reset", 
    "method": "POST", 
    "statusCode": "204", 
    "statusMessage": "No Content" 
    }, 
    { 
    "url": "http://localhost:8080/wst-server-1.0-SNAPSHOT/services/rest/", 
    "path": "3/orders", 
    "method": "POST", 
    "statusCode": "201", 
    "statusMessage": "Created" 
    } 
] 
} 

the code

Gson gson = new Gson(); 
String json = gson.toJson(rs.getString(Columns.REQUEST.getName())); 
logger.info(json); 
ClientTask task = gson.fromJson(json, ClientTask.class); 

logger.info(json) дает следующее

"{\n \"requests\": [\n {\n  \"url\": \"http://localhost:8080/wst-server-1.0-SNAPSHOT/services/rest/\",\n  \"path\": \"3/reset\",\n  \"method\": \"POST\",\n  \"statusCode\": \"204\",\n  \"statusMessage\": \"No Content\"\n },\n {\n  \"url\": \"http://localhost:8080/wst-server-1.0-SNAPSHOT/services/rest/\",\n  \"path\": \"3/orders\",\n  \"method\": \"POST\",\n  \"statusCode\": \"201\",\n  \"statusMessage\": \"Created\"\n }\n ]\n}" 

но gson.fromJson(json, ClientTask.class); линия выдает это исключение

Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 486 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:180) 
at com.google.gson.Gson.fromJson(Gson.java:755) 
at com.google.gson.Gson.fromJson(Gson.java:721) 
at com.google.gson.Gson.fromJson(Gson.java:670) 
at com.google.gson.Gson.fromJson(Gson.java:642) 
at cz.cvut.fit.wst.database.rowmapper.ClientTaskRowMapper.mapRow(ClientTaskRowMapper.java:30) 
at cz.cvut.fit.wst.database.rowmapper.ClientTaskRowMapper.mapRow(ClientTaskRowMapper.java:1) 
at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:92) 
at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:1) 
at org.springframework.jdbc.core.JdbcTemplate$1.doInPreparedStatement(JdbcTemplate.java:648) 
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:586) 
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:636) 
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:665) 
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:673) 
at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:728) 
at cz.cvut.fit.wst.database.management.MySqlManager.getClientTask(MySqlManager.java:132) 
at cz.cvut.fit.wst.client.rest.RestFrontend.main(RestFrontend.java:29) 

Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 486 
at com.google.gson.stream.JsonReader.expect(JsonReader.java:339) 
at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:322) 
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:168) 
... 16 more 

POJOs

public class ClientTask { 

    private String taskTypeId; 
    private String userId; 

    private List<ClientTaskRequest> requests; 

} 

public class ClientTaskRequest { 

    private String url; 
    private String path; 
    private String method; 
    private String body; 
    private String statusCode; 
    private String statusMessage; 
    private String responseParser; 

} 

Я попытался вручную копируем строку регистратором и положить, что право на Gson, и она работала. Так почему же этого не происходит?

Answer 1

Если у вас уже есть JSON в поле базы данных, не сериализуйте его снова.

Все, что вам нужно нужно:

Gson gson = new Gson(); 
String json = rs.getString(Columns.REQUEST.getName()); 
ClientTask task = gson.fromJson(json, ClientTask.class);