com.logisticsShop.utils.JsonUtil.java Source code

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package com.logisticsShop.utils;

/**
 * Copyright 2010 Fuchun.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;

/**
 * ?? {@code JSON} ??
 * <p />
 * ?{@code JSON} ??<a href="http://code.google.com/p/google-gson/"
 * mce_href="http://code.google.com/p/google-gson/" target="_blank"> {@code Google Gson}</a>?
 * ?
 * 
 * <pre>
 * public class User { 
 *     @SerializedName("pwd")
 *     private String password; 
 *     @Expose
 *     @SerializedName("uname")
 *     private String username; 
 *     @Expose
 *     @Since(1.1)
 *     private String gender; 
 *     @Expose
 *     @Since(1.0)
 *     private String sex; 
 *      
 *     public User() {} 
 *     public User(String username, String password, String gender) { 
 *         // user constructor code... ... ... 
 *     } 
 *      
 *     public String getUsername() 
 *     ... ... ... 
 * }
 * List<User> userList = new LinkedList<User>(); 
 * User jack = new User("Jack", "123456", "Male"); 
 * User marry = new User("Marry", "888888", "Female"); 
 * userList.add(jack); 
 * userList.add(marry); 
 * Type targetType = new TypeToken<List<User>>(){}.getType(); 
 * String sUserList1 = JSONUtils.toJson(userList, targetType); 
 * sUserList1 ----> [{"uname":"jack","gender":"Male","sex":"Male"},{"uname":"marry","gender":"Female","sex":"Female"}] 
 * String sUserList2 = JSONUtils.toJson(userList, targetType, false); 
 * sUserList2 ----> [{"uname":"jack","pwd":"123456","gender":"Male","sex":"Male"},{"uname":"marry","pwd":"888888","gender":"Female","sex":"Female"}] 
 * String sUserList3 = JSONUtils.toJson(userList, targetType, 1.0d, true); 
 * sUserList3 ----> [{"uname":"jack","sex":"Male"},{"uname":"marry","sex":"Female"}]
 * </pre>
 * 
 * @author Fuchun
 * @since ay-commons-lang 1.0
 * @version 1.1.0
 */
public class JsonUtil {

    /**  {@code JSON} ? - <code>"{}"</code>?*/
    public static final String EMPTY_JSON = "{}";
    /**  {@code JSON} (?)? - {@code "[]"}?*/
    public static final String EMPTY_JSON_ARRAY = "[]";
    /** ?{@code JSON} /???*/
    public static final String DEFAULT_DATE_PATTERN = "yyyy-MM-dd HH:mm:ss SSS";
    /** {@code Google Gson} ?<code>@Since</code> ?? - {@code 1.0}?*/
    public static final double SINCE_VERSION_10 = 1.0d;
    /** {@code Google Gson} ?<code>@Since</code> ?? - {@code 1.1}?*/
    public static final double SINCE_VERSION_11 = 1.1d;
    /** {@code Google Gson} ?<code>@Since</code> ?? - {@code 1.2}?*/
    public static final double SINCE_VERSION_12 = 1.2d;
    /** {@code Google Gson} ?<code>@Until</code> ?? - {@code 1.0}?*/
    public static final double UNTIL_VERSION_10 = SINCE_VERSION_10;
    /** {@code Google Gson} ?<code>@Until</code> ?? - {@code 1.1}?*/
    public static final double UNTIL_VERSION_11 = SINCE_VERSION_11;
    /** {@code Google Gson} ?<code>@Until</code> ?? - {@code 1.2}?*/
    public static final double UNTIL_VERSION_12 = SINCE_VERSION_12;

    /**
     * <p>
     * <code>JSONUtils</code> instances should NOT be constructed in standard programming. Instead,
     * the class should be used as <code>JSONUtils.fromJson("foo");</code>.
     * </p>
     * <p>
     * This constructor is public to permit tools that require a JavaBean instance to operate.
     * </p>
     */
    public JsonUtil() {
        super();
    }

    /**
     * ????? {@code JSON} ??
     * <p />
     * <b>??????<code>"{}"</code>???<code>"[]"</code> </b>
     * 
     * @param target
     *            ?
     * @param targetType
     *            ?
     * @param isSerializeNulls
     *            ???{@code null} ?
     * @param version
     *            ??
     * @param datePattern
     *            ???
     * @param excludesFieldsWithoutExpose
     *            ??{@literal @Expose} ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Type targetType, boolean isSerializeNulls, Double version,
            String datePattern, boolean excludesFieldsWithoutExpose) {
        if (target == null)
            return EMPTY_JSON;
        GsonBuilder builder = new GsonBuilder();
        if (isSerializeNulls)
            builder.serializeNulls();
        if (version != null)
            builder.setVersion(version.doubleValue());
        builder.setDateFormat(datePattern);
        if (excludesFieldsWithoutExpose)
            builder.excludeFieldsWithoutExposeAnnotation();
        return toJson(target, targetType, builder);
    }

    /**
     * ??{@code JSON} ??b>?????{@code JavaBean} ?/b>
     * <ul>
     * <li>???{@literal @Expose} </li>
     * <li>??{@code null} </li>
     * <li>???{@literal @Since} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target) {
        return toJson(target, null, false, null, null, true);
    }

    /**
     * ??{@code JSON} ??b>?????{@code JavaBean} ?/b>
     * <ul>
     * <li>???{@literal @Expose} </li>
     * <li>??{@code null} </li>
     * <li>???{@literal @Since} </li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param datePattern
     *            ???
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, String datePattern) {
        return toJson(target, null, false, null, datePattern, true);
    }

    /**
     * ??{@code JSON} ??b>?????{@code JavaBean} ?/b>
     * <ul>
     * <li>???{@literal @Expose} </li>
     * <li>??{@code null} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param version
     *            ?({@literal @Since})?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Double version) {
        return toJson(target, null, false, version, null, true);
    }

    /**
     * ??{@code JSON} ??b>?????{@code JavaBean} ?/b>
     * <ul>
     * <li>??{@code null} </li>
     * <li>???{@literal @Since} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param excludesFieldsWithoutExpose
     *            ??{@literal @Expose} ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, boolean excludesFieldsWithoutExpose) {
        return toJson(target, null, false, null, null, excludesFieldsWithoutExpose);
    }

    /**
     * ??{@code JSON} ??b>?????{@code JavaBean} ?/b>
     * <ul>
     * <li>??{@code null} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param version
     *            ?({@literal @Since})?
     * @param excludesFieldsWithoutExpose
     *            ??{@literal @Expose} ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Double version, boolean excludesFieldsWithoutExpose) {
        return toJson(target, null, false, version, null, excludesFieldsWithoutExpose);
    }

    /**
     * ??{@code JSON} ??b>????/b>
     * <ul>
     * <li>???{@literal @Expose} </li>
     * <li>??{@code null} </li>
     * <li>???{@literal @Since} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param targetType
     *            ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Type targetType) {
        return toJson(target, targetType, false, null, null, true);
    }

    /**
     * ??{@code JSON} ??b>????/b>
     * <ul>
     * <li>???{@literal @Expose} </li>
     * <li>??{@code null} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param targetType
     *            ?
     * @param version
     *            ?({@literal @Since})?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Type targetType, Double version) {
        return toJson(target, targetType, false, version, null, true);
    }

    /**
     * ??{@code JSON} ??b>????/b>
     * <ul>
     * <li>??{@code null} </li>
     * <li>???{@literal @Since} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param targetType
     *            ?
     * @param excludesFieldsWithoutExpose
     *            ??{@literal @Expose} ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Type targetType, boolean excludesFieldsWithoutExpose) {
        return toJson(target, targetType, false, null, null, excludesFieldsWithoutExpose);
    }

    /**
     * ??{@code JSON} ??b>????/b>
     * <ul>
     * <li>??{@code null} </li>
     * <li>??/ ??- {@code yyyy-MM-dd HH:mm:ss SSS}?/li>
     * </ul>
     * 
     * @param target
     *            ??? {@code JSON} ?
     * @param targetType
     *            ?
     * @param version
     *            ?({@literal @Since})?
     * @param excludesFieldsWithoutExpose
     *            ??{@literal @Expose} ?
     * @return ?{@code JSON} ??
     * @since 1.0
     */
    public static String toJson(Object target, Type targetType, Double version,
            boolean excludesFieldsWithoutExpose) {
        return toJson(target, targetType, false, version, null, excludesFieldsWithoutExpose);
    }

    /**
     *  {@code JSON} ???
     * 
     * @param <T>
     *            ???
     * @param json
     *            ?{@code JSON} ?
     * @param token
     *            {@code com.google.gson.reflect.TypeToken} ?
     * @param datePattern
     *            ???
     * @return ?{@code JSON} ?
     * @since 1.0
     */
    public static <T> T fromJson(String json, TypeToken<T> token, String datePattern) {
        GsonBuilder builder = new GsonBuilder();
        Gson gson = builder.create();
        try {
            return gson.fromJson(json, token.getType());
        } catch (Exception ex) {
            return null;
        }
    }

    /**
     *  {@code JSON} ???
     * 
     * @param <T>
     *            ???
     * @param json
     *            ?{@code JSON} ?
     * @param token
     *            {@code com.google.gson.reflect.TypeToken} ?
     * @return ?{@code JSON} ?
     * @since 1.0
     */
    public static <T> T fromJson(String json, TypeToken<T> token) {
        return fromJson(json, token, null);
    }

    /**
     *  {@code JSON} ???<b>??? {@code JavaBean} ?/b>
     * 
     * @param <T>
     *            ???
     * @param json
     *            ?{@code JSON} ?
     * @param clazz
     *            ???
     * @param datePattern
     *            ???
     * @return ?{@code JSON} ?
     * @since 1.0
     */
    public static <T> T fromJson(String json, Class<T> clazz, String datePattern) {
        GsonBuilder builder = new GsonBuilder();
        Gson gson = builder.create();
        try {
            return gson.fromJson(json, clazz);
        } catch (Exception ex) {
            return null;
        }
    }

    /**
     *  {@code JSON} ???<b>??? {@code JavaBean} ?/b>
     * 
     * @param <T>
     *            ???
     * @param json
     *            ?{@code JSON} ?
     * @param clazz
     *            ???
     * @return ?{@code JSON} ?
     * @since 1.0
     */
    public static <T> T fromJson(String json, Class<T> clazz) {
        return fromJson(json, clazz, null);
    }

    /**
     * ?{@code GsonBuilder} ?????{@code JSON} ??
     * <p />
     * ?????{@code JavaBean}  <code>"{}"</code>???
     * <code>"[]"</code>??
     * 
     * @param target
     *            ?
     * @param targetType
     *            ?
     * @param builder
     *            ?{@code Gson} ?
     * @return ?{@code JSON} ??
     * @since 1.1
     */
    public static String toJson(Object target, Type targetType, GsonBuilder builder) {
        if (target == null)
            return EMPTY_JSON;
        Gson gson = null;
        if (builder == null) {
            gson = new Gson();
        } else {
            gson = builder.create();
        }
        String result = EMPTY_JSON;
        try {
            if (targetType == null) {
                result = gson.toJson(target);
            } else {
                result = gson.toJson(target, targetType);
            }
        } catch (Exception ex) {
            if (target instanceof Collection<?> || target instanceof Iterator<?> || target instanceof Enumeration<?>
                    || target.getClass().isArray()) {
                result = EMPTY_JSON_ARRAY;
            }
        }
        return result;
    }
}