JSON.java

package org.test4j.json;

import java.io.StringWriter;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.test4j.json.decoder.IDecoder;
import org.test4j.json.decoder.base.DecoderFactory;
import org.test4j.json.encoder.JSONEncoder;
import org.test4j.json.helper.JSONArray;
import org.test4j.json.helper.JSONFeature;
import org.test4j.json.helper.JSONMap;
import org.test4j.json.helper.JSONObject;
import org.test4j.json.helper.JSONScanner;
import org.test4j.json.helper.JSONSingle;

/**
 * json解码，编码工具类
 * 
 * @author darui.wudr
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public final class JSON {

    /**
     * 将json字符串反序列为对象
     * 
     * @param json
     * @return
     */
    public static final <T> T toObject(String json) {
        if (json == null) {
            return null;
        }
        JSONObject jsonObject = JSONScanner.scnJSON(json);

        Object o = toObject(jsonObject, new HashMap<String, Object>());
        return (T) o;
    }

    public static final <T> T toObject(String json, Type clazz) {
        if (json == null) {
            return null;
        }
        JSONObject jsonObject = JSONScanner.scnJSON(json);

        Object o = toObject(jsonObject, clazz, new HashMap<String, Object>());
        return (T) o;
    }

    /**
     * 将json字符串反序列为对象
     * 
     * @param <T>
     * @param json
     * @param clazz
     * @param decodingFeatures
     * @return
     */
    public static final <T> T toObject(JSONObject json, Map<String, Object> references) {
        if (json instanceof JSONArray) {
            Object o = toObject(json, Object[].class, references);
            return (T) o;
        } else if (json instanceof JSONMap) {
            Type toType = ((JSONMap) json).getClazzFromJSONFProp(HashMap.class);
            Object o = toObject(json, toType, references);
            return (T) o;
        } else {
            Object value = ((JSONSingle) json).toPrimitiveValue();
            return (T) value;
        }
    }

    public static final <T> T toObject(JSONObject json, Type type, Map<String, Object> references) {
        if (type == null || Object.class.equals(type) || type instanceof TypeVariable) {
            return toObject(json, references);
        } else {
            IDecoder decoder = DecoderFactory.getDecoder(type);
            Object obj = decoder.decode(json, type, references);
            return (T) obj;
        }
    }

    /**
     * 将对象编码为json串
     * 
     * @param object
     * @return
     */
    public static final String toJSON(Object object, JSONFeature... features) {
        if (object == null) {
            return "null";
        }
        int value = JSONFeature.getFeaturesMask(features);
        String json = toJSON(object, value);
        return json;
    }

    /**
     * 将对象编码为json串
     * 
     * @param object
     * @param features
     * @return
     */
    public static final String toJSON(Object object, int features) {
        if (object == null) {
            return "null";
        }

        StringWriter writer = new StringWriter();
        JSONEncoder encoder = JSONEncoder.get(object.getClass());
        encoder.setFeatures(features);

        List<String> references = new ArrayList<String>();
        encoder.encode(object, writer, references);
        String json = writer.toString();
        return json;
    }
}