Json格式的資料現在已經算是非常通用了，大部分公司的前後端互動的資料格式首選就是json格式的資料，這個工具類JsonUtil可以滿足工作中的大部分需求。

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.sunvalley.hadoop.VO.ApiMsgEnum;
import com.sunvalley.hadoop.VO.BaseReturnVO;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;

/**
 * 類或方法的功能描述 :TODO
 *
 * @author: logan.zou
 * @date: 2018-11-28 18:41
 */
public class JsonUtil {
    private static ObjectMapper objectMapper = new ObjectMapper();
    private static final String RES_CODE = "resCode";
    private static final String RES_Data = "data";
    private static final String RES_DES = "resDes";

    public JsonUtil() {
    }

    public static <T> T fromObject(Object objs, Class<T> type) {
        try {
            String json = toJSON(objs);
            return fromJSON(json, type);
        } catch (Exception var3) {
            throw new RuntimeException(var3);
        }
    }

    public static <T> List<T> fromObjectArray(Object objs, Class<T> type) {
        try {
            String json = toJSON(objs);
            return fromJSONArray(json, type);
        } catch (Exception var3) {
            throw new RuntimeException(var3);
        }
    }

    public static <T> T fromFeign(String json, Class<T> type) {
        try {
            int resultCode = getInteger(json, "resCode");
            if (resultCode != ApiMsgEnum.OK.getResCode()) {
                String resDes = getString(json, "resDes");
                throw new Exception(resDes);
            } else {
                T obj = fromJSON(json, "data", type);
                return obj;
            }
        } catch (Exception var5) {
            throw new RuntimeException(var5);
        }
    }

    public static <T> List<T> fromFeignArray(String jsonStr, Class<T> elementClass) {
        try {
            int resultCode = getInteger(jsonStr, "resCode");
            if (resultCode != ApiMsgEnum.OK.getResCode()) {
                String resDes = getString(jsonStr, "resDes");
                throw new Exception(resDes);
            } else {
                return fromJSONArray(jsonStr, "data", elementClass);
            }
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static <T> List<T> fromJSONArray(String jsonStr, String fieldName, Class<T> elementClass) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            JsonNode jsonNode = node.get(fieldName);
            if (jsonNode == null) {
                return null;
            } else {
                String fieldJson = node.get(fieldName).toString();
                JavaType javaType = objectMapper.getTypeFactory().constructParametricType(ArrayList.class, new Class[]{elementClass});
                return (List)objectMapper.readValue(fieldJson, javaType);
            }
        } catch (Exception var7) {
            throw new RuntimeException(var7);
        }
    }

    public static <T> List<T> fromJSONArray(String jsonStr, Class<T> elementClass) {
        try {
            JavaType javaType = objectMapper.getTypeFactory().constructParametricType(ArrayList.class, new Class[]{elementClass});
            return (List)objectMapper.readValue(jsonStr, javaType);
        } catch (Exception var3) {
            throw new RuntimeException(var3);
        }
    }

    public static <T> T fromJSON(String jsonStr, String fieldName, Class<T> elementClass) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            String fieldJson = node.get(fieldName).toString();
            return objectMapper.readValue(fieldJson, elementClass);
        } catch (Exception var5) {
            throw new RuntimeException(var5);
        }
    }

    public static String getJsonString(String jsonStr, String fieldName) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            JsonNode fieldJson = node.get(fieldName);
            return fieldJson == null ? "" : node.get(fieldName).toString();
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static String getString(String jsonStr, String fieldName) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            JsonNode fieldJson = node.get(fieldName);
            return fieldJson == null ? "" : node.get(fieldName).textValue();
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static Integer getInteger(String jsonStr, String fieldName) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            JsonNode jsonNode = node.get(fieldName);
            return jsonNode == null ? null : castToInt(jsonNode.asText());
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static Integer getInteger(String jsonStr, String fieldName, int defVal) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            JsonNode jsonNode = node.get(fieldName);
            return jsonNode == null ? defVal : castToInt(jsonNode.asText());
        } catch (Exception var5) {
            return defVal;
        }
    }

    public static Long getLong(String jsonStr, String fieldName) {
        try {
            JsonNode node = objectMapper.readTree(jsonStr);
            JsonNode jsonNode = node.get(fieldName);
            return jsonNode == null ? null : castToLong(jsonNode.asText());
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static <T> T fromJSON(String json, Class<T> type) {
        try {
            T obj = objectMapper.readValue(json, type);
            return obj;
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static <T> T fromJSON(BaseReturnVO baseReturnVO, Class<T> type) {
        try {
            String json = toJson(baseReturnVO.getData());
            T obj = objectMapper.readValue(json, type);
            return obj;
        } catch (Exception var4) {
            throw new RuntimeException(var4);
        }
    }

    public static <T> T fromJSON(String source, TypeReference<T> ref) throws Exception {
        Object rtn = null;

        try {
            rtn = objectMapper.readValue(source, ref);
            return (T) rtn;
        } catch (IOException var4) {
            throw var4;
        }
    }

    public static <T> List<T> fromJSON(String jsonStr, Class<?> collectionClass, Class<T> elementClass) throws Exception {
        try {
            JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass, new Class[]{elementClass});
            return (List)objectMapper.readValue(jsonStr, javaType);
        } catch (Exception var4) {
            throw var4;
        }
    }

    public static <T> String toJSON(T obj) {
        try {
            String jsonStr = objectMapper.writeValueAsString(obj);
            return jsonStr;
        } catch (Exception var3) {
            throw new RuntimeException(var3);
        }
    }

    public static String toJson(Object object) throws Exception {
        return objectMapper.writeValueAsString(object);
    }

    private static Integer castToInt(Object value) {
        if (value == null) {
            return null;
        } else if (value instanceof Integer) {
            return (Integer)value;
        } else if (value instanceof Number) {
            return ((Number)value).intValue();
        } else if (value instanceof String) {
            String strVal = (String)value;
            if (strVal.length() != 0 && !"null".equals(strVal) && !"NULL".equals(strVal)) {
                if (strVal.indexOf(44) != 0) {
                    strVal = strVal.replaceAll(",", "");
                }

                return Integer.parseInt(strVal);
            } else {
                return null;
            }
        } else {
            return value instanceof Boolean ? (Boolean)value ? 1 : 0 : null;
        }
    }

    private static Long castToLong(Object value) {
        if (value == null) {
            return null;
        } else if (value instanceof Number) {
            return ((Number)value).longValue();
        } else if (value instanceof String) {
            String strVal = (String)value;
            if (strVal.length() != 0 && !"null".equals(strVal) && !"NULL".equals(strVal)) {
                if (strVal.indexOf(44) != 0) {
                    strVal = strVal.replaceAll(",", "");
                }

                try {
                    return Long.parseLong(strVal);
                } catch (NumberFormatException var3) {
                    return null;
                }
            } else {
                return null;
            }
        } else {
            return null;
        }
    }

    static {
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
    }
}
 

程式碼中使用到的 BaseReturnVO

public class BaseReturnVO implements Serializable {
    protected int resCode;
    protected String resDes;
    protected Object data;

    public int getResCode() {
        return this.resCode;
    }

    public void setResCode(int resCode) {
        this.resCode = resCode;
    }

    public String getResDes() {
        return this.resDes;
    }

    public void setResDes(String resDes) {
        this.resDes = resDes;
    }

    public Object getData() {
        return this.data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    public BaseReturnVO() {
    }

    public BaseReturnVO(int code, String msg) {
        this.resCode = code;
        this.resDes = msg;
        this.data = "";
    }

    public BaseReturnVO(int code, Exception e) {
        this.resCode = code;
        this.resDes = e.getMessage();
        this.data = "";
    }

    public BaseReturnVO(int code, String msg, Exception e) {
        this.resCode = code;
        this.resDes = msg;
        this.data = "";
    }

    public BaseReturnVO(Object data) {
        this.resCode = ApiMsgEnum.OK.getResCode();
        this.resDes = ApiMsgEnum.OK.getResDes();
        this.data = data;
    }

    public BaseReturnVO(Exception exp) {
        this.resCode = 500;
        this.resDes = exp.getMessage();
        this.data = "";
    }

    public BaseReturnVO(ApiMsgEnum msgEnum) {
        this.resCode = msgEnum.getResCode();
        this.resDes = msgEnum.getResDes();
        this.data = "";
    }
}
 

程式碼中使用到的列舉類 ApiMsgEnum

public enum ApiMsgEnum {
    OK(200, "OK"),
    BAD_REQUEST(400, "Bad Request"),
    NOT_FOUND(404, "Not Found"),
    UNAUTHORIZED(401, "Unauthorized"),
    FORBIDDEN(403, "Forbidden"),
    INTERNAL_SERVER_ERROR(500, "Internal Server Error"),
    BAD_GATEWAY(502, "Bad Gateway"),
    SERVICE_UNAVAILABLE(503, "Service Unavailable"),
    GATEWAY_TIMEOUT(504, "Gateway Timeout"),
    COMMON_SERVER_ERROR(10000, "COMMON_SERVER_ERROR"),
    USER_SERVER_ERROR(11000, "USER_SERVER_ERROR"),
    USER_REDIS_ERROR(11001, "USER_REDIS_ERROR"),
    PRODUCT_SERVER_ERROR(12000, "PRODUCT_SERVER_ERROR"),
    PRODUCT_PARAMETER_ERROR(12001, "PRODUCT_PARAMETER_ERROR"),
    PRODUCT_BOM_ERROR(12002, "PRODUCT_SERVER_ERROR"),
    ORDER_SERVER_ERROR(13000, "ORDER_SERVER_ERROR"),
    CUSTOMER_SERVER_ERROR(13000, "CUSTOMER_SERVER_ERROR");

    private int resCode;
    private String resDes;
    public static Map<Integer, String> apiMsgMap = new HashMap();

    private ApiMsgEnum(int code, String msg) {
        this.resCode = code;
        this.resDes = msg;
    }

    private static Map<Integer, String> getAll() {
        Map<Integer, String> retMap = new LinkedHashMap();
        ApiMsgEnum[] enumArr = values();
        ApiMsgEnum[] var2 = enumArr;
        int var3 = enumArr.length;

        for(int var4 = 0; var4 < var3; ++var4) {
            ApiMsgEnum aEnum = var2[var4];
            retMap.put(aEnum.getResCode(), aEnum.getResDes());
        }

        return retMap;
    }

    public int getResCode() {
        return this.resCode;
    }

    public void setResCode(int resCode) {
        this.resCode = resCode;
    }

    public String getResDes() {
        return this.resDes;
    }

    public void setResDes(String resDes) {
        this.resDes = resDes;
    }

    static {
        apiMsgMap = getAll();
    }
}