JSON类的JavaDoc
This is the main class for using Fastjson. You usually call these two methods toJSONString(Object) and parseObject(String, Class).
Here is an example of how fastjson is used for a simple Class:
Model model = new Model();
String json = JSON.toJSONString(model); // serializes model to Json
Model model2 = JSON.parseObject(json, Model.class); // deserializes json into model2
If the object that your are serializing/deserializing is a ParameterizedType
(i.e. contains at least one type parameter and may be an array) then you must use the
toJSONString(Object) or parseObject(String, Type, Feature[]) method. Here is an
example for serializing and deserialing a ParameterizedType:
String json = "[{},...]";
Type listType = new TypeReference<List<Model>>() {}.getType();
List<Model> modelList = JSON.parseObject(json, listType);
ParameterizedType
ParameterizedType是Type的子接口，表示一个有参数的类型，例如Collection<T>，Map<K,V>等。但实现上 ParameterizedType并不直接表示Collection<T>和Map<K,V>等，而是表示 Collection<String>和Map<String,String>等这种具体的类型。是不是看着眼熟，其实这就是我们常说的泛型。而ParameterizedType代表的是一个泛型的实例，我们就称ParameterizedType为“泛型实例”吧。
当创建泛型P（如：Collection<String>）时，将解析P实例化的泛型类型声明（如：Collection<T>），并且递归地创建P的所有泛型参数（如：String）。
实现这个接口的“类”必须实现一个equals()方法，该方法将任何“泛型类型”（如：Collection<T>）声明相同且“类型参数”（如：String）也相同的两个“类”等同起来。
JSON属性
public static TimeZone defaultTimeZone = TimeZone.getDefault();public static Locale defaultLocale = Locale.getDefault();public static String DEFAULT_TYPE_KEY = "@type";static final SerializeFilter[] emptyFilters = new SerializeFilter[0];public static String DEFFAULT_DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";public static int DEFAULT_PARSER_FEATURE;public static int DEFAULT_GENERATE_FEATURE;private static final ConcurrentHashMap<Type, Type> mixInsMapper = new ConcurrentHashMap<Type, Type>(16);static {int features = 0;features |= Feature.AutoCloseSource.getMask();features |= Feature.InternFieldNames.getMask();features |= Feature.UseBigDecimal.getMask();features |= Feature.AllowUnQuotedFieldNames.getMask();features |= Feature.AllowSingleQuotes.getMask();features |= Feature.AllowArbitraryCommas.getMask();features |= Feature.SortFeidFastMatch.getMask();features |= Feature.IgnoreNotMatch.getMask();DEFAULT_PARSER_FEATURE = features;}static {int features = 0;features |= SerializerFeature.QuoteFieldNames.getMask();features |= SerializerFeature.SkipTransientField.getMask();features |= SerializerFeature.WriteEnumUsingName.getMask();features |= SerializerFeature.SortField.getMask();DEFAULT_GENERATE_FEATURE = features;config(IOUtils.DEFAULT_PROPERTIES);}
配置方法
private static void config(Properties properties)
public static void setDefaultTypeKey(String typeKey)
核心方法
parse()
public static Object parse(String text){}
public static Object parse(String text, int features){}
public static Object parse(String text, Feature... features){}
public static Object parse(String text, ParserConfig config){}
public static Object parse(String text, ParserConfig config, Feature... features){}
public static Object parse(String text, ParserConfig config, int features){}public static Object parse(byte[] input, Feature... features){}
public static Object parse(byte[] input, int off, int len, CharsetDecoder charsetDecoder, int features) {}
parseObject()
public static JSONObject parseObject(String text)
public static <T> T parseObject(String text, Class<T> clazz)
public static JSONObject parseObject(String text, Feature... features)public static <T> T parseObject(String text, TypeReference<T> type, Feature... features) public static <T> T parseObject(String json, Class<T> clazz, Feature... features)public static <T> T parseObject(String text, Class<T> clazz, ParseProcess processor, Feature... features)public static <T> T parseObject(String json, Type type, Feature... features)public static <T> T parseObject(String input, Type clazz, ParseProcess processor, Feature... features)public static <T> T parseObject(String input, Type clazz, int featureValues, Feature... features)public static <T> T parseObject(String input, Type clazz, ParserConfig config, Feature... features)public static <T> T parseObject(String input, Type clazz, ParserConfig config, int featureValues, Feature... features)public static <T> T parseObject(String input, Type clazz, ParserConfig config, ParseProcess processor, int featureValues, Feature... features)public static <T> T parseObject(byte[] bytes, Type clazz, Feature... features)public static <T> T parseObject(byte[] bytes, int offset, int len, Charset charset, Type clazz, Feature... features)public static <T> T parseObject(byte[] bytes, Charset charset, Type clazz, ParserConfig config, ParseProcess processor, int featureValues, Feature... features)public static <T> T parseObject(byte[] bytes, int offset, int len, Charset charset, Type clazz, ParserConfig config, ParseProcess processor, int featureValues, Feature... features)public static <T> T parseObject(byte[] input, int off, int len, CharsetDecoder charsetDecoder, Type clazz, Feature... features)public static <T> T parseObject(char[] input, int length, Type clazz, Feature... features)
public static <T> T parseObject(InputStream is, Type type, Feature... features)
public static <T> T parseObject(InputStream is, Charset charset, Type type, ParserConfig config, ParseProcess processor, int featureValues, Feature... features)
这parse()和parseObject()方法大同小异，最终都是通过实例化一个DefaultJSONParser来进行解析处理，只是可能会对DefaultJSONParser设置不同的属性参数，然后通过DefaultJSONParser.parse()和DefaultJSONParser.parseObject()方法来进行处理和操作。
DefaultJSONParser
构造函数，最终均使用该构造函数，仅在参数上有所区分
public DefaultJSONParser(final Object input, final JSONLexer lexer, final ParserConfig config){this.lexer = lexer;this.input = input;this.config = config;this.symbolTable = config.symbolTable;int ch = lexer.getCurrent();if (ch == '{') {lexer.next();((JSONLexerBase) lexer).token = JSONToken.LBRACE;} else if (ch == '[') {lexer.next();((JSONLexerBase) lexer).token = JSONToken.LBRACKET;} else {lexer.nextToken(); // prime the pump}}
除此外，parseObject()方法还会设置其它参数
if (processor != null) {if (processor instanceof ExtraTypeProvider) {parser.getExtraTypeProviders().add((ExtraTypeProvider) processor);}if (processor instanceof ExtraProcessor) {parser.getExtraProcessors().add((ExtraProcessor) processor);}if (processor instanceof FieldTypeResolver) {parser.setFieldTypeResolver((FieldTypeResolver) processor);}
}
DefaultJSONParser.parse()
1、找到对应的ObjectDeserializer
2、序列化操作
2.1、找出Object对应的field及fieldClass（属性类型）
public static JavaBeanInfo build(Class<?> clazz //, Type type //, PropertyNamingStrategy propertyNamingStrategy //, boolean fieldBased //, boolean compatibleWithJavaBean, boolean jacksonCompatible)public static Field getField(Class<?> clazz, String fieldName, Field[] declaredFields)