json字符串与Object、List、Map的互转工具类详解编程语言

import java.io.FileReader;   
import java.io.FileWriter;   
import java.io.IOException;   
import java.io.StringWriter;   
import java.util.List;   
import java.util.Map;   
   
import org.codehaus.jackson.JsonFactory;   
import org.codehaus.jackson.JsonGenerationException;   
import org.codehaus.jackson.JsonGenerator;   
import org.codehaus.jackson.JsonNode;   
import org.codehaus.jackson.JsonParseException;   
import org.codehaus.jackson.map.JsonMappingException;   
import org.codehaus.jackson.map.ObjectMapper;   
import org.codehaus.jackson.map.SerializationConfig;   
import org.codehaus.jackson.map.annotate.JsonSerialize;   
   
import com.alibaba.fastjson.JSONArray;   
   
/**  
 * Json工具类，实现JSON与Java Bean的互相转换  
 * User: shijing  
 * <span style="font-family: Arial, Helvetica, sans-serif;">2015年4月3日上午10:42:19  
 */   
   
public class JsonUtils {   
   
    private static ObjectMapper objectMapper = new ObjectMapper();   
    private static JsonFactory jsonFactory = new JsonFactory();   
   
    static {   
        objectMapper.configure(SerializationConfig.Feature.WRITE_NULL_MAP_VALUES, false);   
        objectMapper.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);   
    }   
   
    /**  
     * 泛型返回，json字符串转对象  
     * 2015年4月3日上午10:42:19  
     * auther:shijing  
     * @param jsonAsString  
     * @param pojoClass  
     * @return  
     * @throws JsonMappingException  
     * @throws JsonParseException  
     * @throws IOException  
     */   
    public static <T> T fromJson(String jsonAsString, Class<T> pojoClass) throws JsonMappingException,   
            JsonParseException, IOException {   
        return objectMapper.readValue(jsonAsString, pojoClass);   
    }   
   
    public static <T> T fromJson(FileReader fr, Class<T> pojoClass) throws JsonParseException, IOException {   
        return objectMapper.readValue(fr, pojoClass);   
    }   
   
    /**  
     * Object对象转json  
     * 2015年4月3日上午10:41:53  
     * auther:shijing  
     * @param pojo  
     * @return  
     * @throws JsonMappingException  
     * @throws JsonGenerationException  
     * @throws IOException  
     */   
    public static String toJson(Object pojo) throws JsonMappingException, JsonGenerationException, IOException {   
        return toJson(pojo, false);   
    }   
   
    public static String toJson(Object pojo, boolean prettyPrint) throws JsonMappingException, JsonGenerationException,   
            IOException {   
        StringWriter sw = new StringWriter();   
        JsonGenerator jg = jsonFactory.createJsonGenerator(sw);   
        if (prettyPrint) {   
            jg.useDefaultPrettyPrinter();   
        }   
        objectMapper.writeValue(jg, pojo);   
        return sw.toString();   
    }   
   
    public static void toJson(Object pojo, FileWriter fw, boolean prettyPrint) throws JsonMappingException,   
            JsonGenerationException, IOException {   
        JsonGenerator jg = jsonFactory.createJsonGenerator(fw);   
        if (prettyPrint) {   
            jg.useDefaultPrettyPrinter();   
        }   
        objectMapper.writeValue(jg, pojo);   
    }   
   
    /**  
     * json字符串转Map  
     * 2015年4月3日上午10:41:25  
     * auther:shijing  
     * @param jsonStr  
     * @return  
     * @throws IOException  
     */   
    public static Map<String, Object> parseMap(String jsonStr) throws IOException {   
        Map<String, Object> map = objectMapper.readValue(jsonStr, Map.class);   
        return map;   
    }   
   
    public static JsonNode parse(String jsonStr) throws IOException {   
        JsonNode node = null;   
        node = objectMapper.readTree(jsonStr);   
        return node;   
    }   
   
    public static ObjectMapper getObjectMapper() {   
        return objectMapper;   
    }   
       
    /**  
     * json字符串转 List对象  
     * 2015年4月2日上午10:22:20  
     * auther:shijing  
     * @param str   json字符串  
     * @param clazz 转换的类型  
     * @return  
     */   
    public static <T> List<T> fromListJson(String str,Class<T> clazz){   
        return JSONArray.parseArray(str, clazz);   
    }   
   
}