转json工具类

package com.csf.practicetest.json;


import com.csf.practicetest.json.entity.RespObj;
import com.csf.practicetest.json.entity.XcfRpoertAnalyseSimplify;

import java.text.ParseException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 测试类
 */
public class JsonTest {

    public static void main2(String[] args) {
        Map<String, Object> obj = new HashMap<String, Object>();
        obj.put("k1", "k1v");
        obj.put("k2", 2);
        try {
            obj.put("k3", JsonUtil.parseDate("2013-01-02"));
        } catch (ParseException e) {
            e.printStackTrace();
        }
        System.out.println(JsonUtil.toJson(obj));
        System.out.println(JsonUtil.toJson(obj, "yyyy-MM-dd"));
        System.out.println(JsonUtil.toJson(obj));

    }

    /**
     * {"code":"200","type":"SUCCESS","message":[{"name":"2011-2015年公司海外营业收入（单位：亿元）","url":"report/AP201610270029422533/img-0140.png","id":"AP201607260016744779","dt":"20170108010655","p":null},{"name":"2011-2015年公司海外营业收入（单位：亿元）","url":"report/AP201610270029422533/img-0140.png","id":"AP201607260016744779","dt":"20170108010655","p":null}]}
     * JavaBean 转为json字符串 
     *
     * @param args
     */
    public static void main(String[] args) {
        Object message = getMessage();

        RespObj res = new RespObj();
        res.setCode("200");
        res.setType("SUCCESS");
        res.setMessage(message);

        System.out.println(JsonUtil.toJson(res));
    }

    public static Object getMessage() {
        List<XcfRpoertAnalyseSimplify> list = new ArrayList<XcfRpoertAnalyseSimplify>();
        XcfRpoertAnalyseSimplify entity = new XcfRpoertAnalyseSimplify();
        entity.setId("AP201605190014926455");
        entity.setDt("20170108003552");
        entity.setName("公司近年净利润及增长情况");
        entity.setUrl("report/AP201605190014926455/img-0139.png");
        list.add(entity);

        entity.setId("AP201607260016744779");
        entity.setDt("20170108010655");
        entity.setName("2011-2015年公司海外营业收入（单位：亿元）");
        entity.setUrl("report/AP201610270029422533/img-0140.png");
        list.add(entity);
        return list;
    }

}


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package com.csf.practicetest.json;

import com.google.gson.*;
import com.google.gson.reflect.TypeToken;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

import java.lang.reflect.Type;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

/**
 * json 转换工具  由对象转化为json
 *
 *  <!--json使用的包-->
 *  <dependency>
 *      <groupId>com.google.code.gson</groupId>
 *       <artifactId>gson</artifactId>
 *      <version>2.3.1</version>
 *      <scope>compile</scope>
 *  </dependency>

 *  <dependency>
 *      <groupId>commons-lang</groupId>
 *      <artifactId>commons-lang</artifactId>
 *      <version>2.6</version>
 *  </dependency>
 */
public class JsonUtil {

    private static final Logger logger = Logger.getLogger("JsonUtil.class");

    public static final String EMPTY_JSON = "{}";
    public static final String EMPTY_JSON_ARRAY = "[]";

    private JsonUtil() {
    }

    private static final GsonBuilder builder = new GsonBuilder();

    private static final Gson gson = builder.serializeNulls().serializeSpecialFloatingPointValues()
            .registerTypeAdapter(Date.class, new JsonUtil().new JsonDateDeserializer()).create();

    /**
     * by default,this method allows serialize null-value properties
     */
    public static String toJson(Object src) {
        if (src == null) {
            return EMPTY_JSON;
        }
        return gson.toJson(src);
    }

    /**
     * default is medium : Mar 8, 2013 12:00:00 AM
     * @param obj
     * @param dateFormat
     *            Note that this pattern must abide by the convention provided
     *            by SimpleDateFormat class.
     */
    public static String toJson(Object obj, String dateFormat) {
        if (obj == null) {
            return EMPTY_JSON;
        } else if (StringUtils.isBlank(dateFormat)) {
            return gson.toJson(obj);
        }

        try {
            return builder.setDateFormat(dateFormat).serializeSpecialFloatingPointValues().create().toJson(obj);
        } catch (Exception e) {

            logger.error("Exception for toJson(obj, dateFormat) : " + e.getMessage());
            return gson.toJson(obj);
        }
    }

    public static String toJson(Object target, Type targetType) {

        String result = EMPTY_JSON;

        if (target == null)
            return result;

        try {
            if (targetType != null) {
                result = gson.toJson(target, targetType);
            } else {
                result = gson.toJson(target);
            }
        } catch (Exception ex) {
            logger.error("JsonUtil.toJson(target, targetType) exception, return empty json, exception for "
                    + target.toString() + " : " + ex.getMessage());
            if (target instanceof Collection || target instanceof Iterator || target instanceof Enumeration
                    || target.getClass().isArray()) {
                result = EMPTY_JSON_ARRAY;
            } else
                result = EMPTY_JSON;
        }
        return result;
    }

    /**
     * to covert a string to a class
     * @param json
     * @param classOfT
     */
    public static <T> T fromJson(String json, Class<T> classOfT) {
        return gson.fromJson(json, classOfT);
    }

    /**
     * to covert a string to a class
     * @param json
     * @param classOfT
     */
    public static <T> T fromJson(String json, Class<T> classOfT, String dateFormat) {
        return builder.setDateFormat(dateFormat).serializeSpecialFloatingPointValues().create().fromJson(json, classOfT);
    }

    public static <T> T fromJson(String json, Type type) {
        return gson.fromJson(json, type);
    }

    /**
     * to covert a JsonElement to a class
     * @param json
     * @param classOfT
     */
    public static <T> T fromJson(JsonElement jsonElem, Class<T> classOfT) {
        return gson.fromJson(jsonElem, classOfT);
    }

    /**
     * convert json string to list
     * @param jsonStr
     * @param type
     */
    public static List<?> jsonToList(String json, Type type) {
        List<?> objList = gson.fromJson(json, type);
        return objList;
    }

    /**
     * convert json to map
     * @param jsonStr
     */
    public static Map<?, ?> jsonToMap(String json) {
        Type type = new TypeToken<Map<?, ?>>() {
        }.getType();
        Map<?, ?> objMap = gson.fromJson(json, type);
        return objMap;
    }

    public static void main(String[] args) {
        Map<String, Object> obj = new HashMap<String, Object>();
        obj.put("k1", "k1v");
        obj.put("k2", 2);
        try {
            obj.put("k3", parseDate("2013-01-02"));
        } catch (ParseException e) {
            e.printStackTrace();
        }
        System.out.println(JsonUtil.toJson(obj));
        System.out.println(JsonUtil.toJson(obj, "yyyy-MM-dd"));
        System.out.println(JsonUtil.toJson(obj));

    }

    public class JsonDateDeserializer implements JsonDeserializer<Date> {
        public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
                throws JsonParseException {
            String s = json.getAsJsonPrimitive().getAsString();
            try {
                return parseDate(s);
            } catch (ParseException e) {
                throw new JsonParseException(e);
            }
        }
    }

    public static Date parseDate(String s) throws ParseException {
        if (s.indexOf("-") == 4) {
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
            return df.parse(s);
        }
        String value = s;
        if (!value.endsWith("d")) {
            if (value.charAt(2) == '/')
                return new SimpleDateFormat("MM/dd/yy").parse(value);
            else
                return new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy").parse(value);
        } else {
            value = value.substring(0, value.length() - 1);
            if (value != null) {
                if (value.startsWith(""") && value.endsWith("""))
                    return new SimpleDateFormat(""ddMMMyy"").parse(value);
                else if (value.startsWith("'") && value.endsWith("'"))
                    return new SimpleDateFormat("''ddMMMyy''").parse(value);
                else
                    throw new ParseException("incorrect format for Date(" + s + "): correct format is 'ddMMMyy'd", 0);
            }
        }
        return null;
    }

}

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package com.csf.practicetest.json.entity;

import java.io.Serializable;

public class RespObj implements Serializable {

    private String code;
    private String type;
    private Object message;

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getType() {
        return type;
    }

    public Object getMessage() {
        return message;
    }

    public void setMessage(Object message) {
        this.message = message;
    }

    public void setType(String type) {
        this.type = type;
    }

}
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package com.csf.practicetest.json.entity;


/**
 * @author fenglei.ma 2017年1月6日 16:52
 */
public class XcfRpoertAnalyseSimplify {

    private String name;// 图片名称
    private String url;// 图片url
    private String id;// 图片编号
    private String dt;
    private String p;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getDt() {
        return dt;
    }

    public void setDt(String dt) {
        this.dt = dt;
    }

    public String getP() {
        return p;
    }

    public void setP(String p) {
        this.p = p;
    }

    @Override
    public String toString() {
        return "XcfRpoertAnalyseSimplify [name=" + name + ", url=" + url + ", id=" + id + ", dt=" + dt + ", p=" + p
                + "]";
    }

}