Module com.google.gson

Package com.google.gson

Class JsonParser

java.lang.Object

com.google.gson.JsonParser

public final class JsonParser
extends Object

A parser to parse JSON into a parse tree of JsonElements.

The JSON data is parsed in lenient mode.

Here's an example of parsing from a string:

 String json = "{\"key\": \"value\"}";
 JsonElement jsonElement = JsonParser.parseString(json);
 JsonObject jsonObject = jsonElement.getAsJsonObject();
 

It can also parse from a reader:

 try (Reader reader = new FileReader("my-data.json", StandardCharsets.UTF_8)) {
   JsonElement jsonElement = JsonParser.parseReader(reader);
   JsonObject jsonObject = jsonElement.getAsJsonObject();
 }
 

If you want to parse from a JsonReader for more customized parsing requirements, the following example demonstrates how to achieve it:

 String json = "{\"skipObj\": {\"skipKey\": \"skipValue\"}, \"obj\": {\"key\": \"value\"}}";
 try (JsonReader jsonReader = new JsonReader(new StringReader(json))) {
   jsonReader.beginObject();
   while (jsonReader.hasNext()) {
     String fieldName = jsonReader.nextName();
     if (fieldName.equals("skipObj")) {
       jsonReader.skipValue();
     } else {
       JsonElement jsonElement = JsonParser.parseReader(jsonReader);
       JsonObject jsonObject = jsonElement.getAsJsonObject();
     }
   }
   jsonReader.endObject();
 }
 

Since:

1.3

Author:

Inderjeet Singh, Joel Leitch

Constructor Summary

Constructors

Constructor	Description
JsonParser()	Deprecated. No need to instantiate this class, use the static methods instead.

Method Summary

Modifier and Type	Method	Description
JsonElement	parse(JsonReader json)	Deprecated. Use parseReader(JsonReader)
JsonElement	parse(Reader json)	Deprecated. Use parseReader(Reader)
JsonElement	parse(String json)	Deprecated. Use parseString(java.lang.String)
static JsonElement	parseReader(JsonReader reader)	Returns the next value from the JSON stream as a parse tree.
static JsonElement	parseReader(Reader reader)	Parses the complete JSON string provided by the reader into a parse tree.
static JsonElement	parseString(String json)	Parses the specified JSON string into a parse tree.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JsonParser

@Deprecated
public JsonParser()

Deprecated.

No need to instantiate this class, use the static methods instead.

Method Detail

parseString

public static JsonElement parseString(String json)
                               throws JsonSyntaxException

Parses the specified JSON string into a parse tree. An exception is thrown if the JSON string has multiple top-level JSON elements, or if there is trailing data.

The JSON string is parsed in lenient mode.

Parameters:

json - JSON text

Returns:

a parse tree of JsonElements corresponding to the specified JSON

Throws:

JsonParseException - if the specified text is not valid JSON

JsonSyntaxException

Since:

2.8.6

parseReader

public static JsonElement parseReader(Reader reader)
                               throws JsonIOException,
                                      JsonSyntaxException

Parses the complete JSON string provided by the reader into a parse tree. An exception is thrown if the JSON string has multiple top-level JSON elements, or if there is trailing data.

The JSON data is parsed in lenient mode.

Parameters:

reader - JSON text

Returns:

a parse tree of JsonElements corresponding to the specified JSON

Throws:

JsonParseException - if there is an IOException or if the specified text is not valid JSON

JsonIOException

JsonSyntaxException

Since:

2.8.6

parseReader

public static JsonElement parseReader(JsonReader reader)
                               throws JsonIOException,
                                      JsonSyntaxException

Returns the next value from the JSON stream as a parse tree. Unlike the other parse methods, no exception is thrown if the JSON data has multiple top-level JSON elements, or if there is trailing data.

If the strictness of the reader is Strictness.STRICT, that strictness will be used for parsing. Otherwise the strictness will be temporarily changed to Strictness.LENIENT and will be restored once this method returns.

Throws:

JsonParseException - if there is an IOException or if the specified text is not valid JSON

JsonIOException

JsonSyntaxException

Since:

2.8.6

parse

@Deprecated
@InlineMe(replacement="JsonParser.parseString(json)",
          imports="com.google.gson.JsonParser")
public JsonElement parse(String json)
                  throws JsonSyntaxException

Deprecated.

Use parseString(java.lang.String)

Throws:

JsonSyntaxException

parse

@Deprecated
@InlineMe(replacement="JsonParser.parseReader(json)",
          imports="com.google.gson.JsonParser")
public JsonElement parse(Reader json)
                  throws JsonIOException,
                         JsonSyntaxException

Deprecated.

Use parseReader(Reader)

Throws:

JsonIOException

JsonSyntaxException

parse

@Deprecated
@InlineMe(replacement="JsonParser.parseReader(json)",
          imports="com.google.gson.JsonParser")
public JsonElement parse(JsonReader json)
                  throws JsonIOException,
                         JsonSyntaxException

Deprecated.

Use parseReader(JsonReader)

Throws:

JsonIOException

JsonSyntaxException