com.feilong.json.JsonHelper Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of feilong Show documentation
Show all versions of feilong Show documentation
feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Copyright (C) 2008 feilong
*
* 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.
*/
package com.feilong.json;
import static com.feilong.core.lang.ObjectUtil.defaultIfNull;
import static com.feilong.json.builder.JsonConfigBuilder.DEFAULT_JAVA_TO_JSON_CONFIG;
import static com.feilong.lib.json.ToStringUtil.ARRAY_END;
import static com.feilong.lib.json.ToStringUtil.ARRAY_START;
import static com.feilong.lib.json.ToStringUtil.OBJECT_END;
import static com.feilong.lib.json.ToStringUtil.OBJECT_START;
import java.util.Iterator;
import java.util.Map;
import com.feilong.core.lang.ClassUtil;
import com.feilong.core.lang.ObjectUtil;
import com.feilong.lib.collection4.IteratorUtils;
import com.feilong.lib.json.JSON;
import com.feilong.lib.json.JSONArray;
import com.feilong.lib.json.JSONArrayBuilder;
import com.feilong.lib.json.JSONObject;
import com.feilong.lib.json.JSONObjectBuilder;
import com.feilong.lib.json.JSONTokener;
import com.feilong.lib.json.JsonConfig;
import com.feilong.lib.json.ToStringUtil;
import com.feilong.lib.json.processors.JsonValueProcessor;
import com.feilong.lib.json.util.JSONUtils;
import com.feilong.lib.lang3.ClassUtils;
/**
* json处理的辅助类.
*
* @author feilong
* @since 1.9.4
*/
public final class JsonHelper{
/** 单利模式. */
private static final JsonConfig DEFAULT_JSON_CONFIG_INSTANCE = new JsonConfig();
//---------------------------------------------------------------
/** Don't let anyone instantiate this class. */
private JsonHelper(){
//AssertionError不是必须的. 但它可以避免不小心在类的内部调用构造器. 保证该类在任何情况下都不会被实例化.
//see 《Effective Java》 2nd
throw new AssertionError("No " + getClass().getName() + " instances for you!");
}
//---------------------------------------------------------------
// [start]toJSON
/**
* 把实体Bean、Map对象、数组、列表集合转换成{@link JSON}.
*
* 说明:
*
*
*
* - 如果
null==jsonConfig,将使用 {@link #DEFAULT_JAVA_TO_JSON_CONFIG}
*
* -
*
*
* 以下类型将转成{@link JSONArray}:
*
*
*
* - 如果是字符串,当是以"["符号开头,"]"符号结尾的时候
* - 数组 obj.getClass().isArray()||obj instanceof Object[]
* - 集合 obj instanceof Collection
* - 枚举 obj instanceof Enum
* - 迭代器 obj instanceof Iterator
*
*
*
* - 其他类型转成 {@link JSONObject}
*
*
*
* @param obj
* 可以是数组,字符串,枚举,集合,map,Java bean,Iterator等类型,内部自动识别转成{@link JSONArray}还是{@link JSONObject}
* @param jsonConfig
* the json config
* @return the json
* @see com.feilong.lib.json.util.JSONUtils#isArray(Object)
* @see java.lang.Class#isEnum()
* @see com.feilong.lib.json.JsonConfig#registerJsonValueProcessor(Class, JsonValueProcessor)
* @see "org.apache.commons.collections4.IteratorUtils#toList(Iterator)"
* @see "org.apache.commons.collections4.IteratorUtils#toList(Iterator, int)"
* @see com.feilong.lib.json.JSONSerializer#toJSON(Object)
*/
public static JSON toJSON(Object obj,JsonConfig jsonConfig){
JsonConfig useJsonConfig = defaultIfNull(jsonConfig, DEFAULT_JAVA_TO_JSON_CONFIG);
if (isNeedConvertToJSONArray(obj)){
Object arrayJsonObject = obj instanceof Iterator//
? IteratorUtils.toList((Iterator) obj)
: obj;
return toJSONArray(arrayJsonObject, useJsonConfig);
}
return toJSONObject(obj, useJsonConfig);
}
//---------------------------------------------------------------
/**
* 是否需要转成 {@link JSONArray}类型.
*
* 以下类型将转成{@link JSONArray}:
*
*
* - 如果是字符串,当是以"["符号开头,"]"符号结尾的时候
* - 数组 obj.getClass().isArray()||obj instanceof Object[]
* - 集合 obj instanceof Collection
* - 枚举 obj instanceof Enum
* - 迭代器 obj instanceof Iterator
*
*
*
* @param obj
* the obj
* @return true, if is need convert to JSON array
* @see com.feilong.lib.json.util.JSONUtils#isArray(Object)
*/
private static boolean isNeedConvertToJSONArray(Object obj){
if (obj instanceof String){
String str = (String) obj;
if (str.startsWith(OBJECT_START) && str.endsWith(OBJECT_END)){// [] 格式的字符串
return true;
}
}
return JSONUtils.isArray(obj) || //
obj instanceof Enum || // obj.getClass().isEnum()这么写 null会报错// object' is an Enum. Use JSONArray instead
obj instanceof Iterator;
}
//---------------------------------------------------------------
/**
* 是否是普通的字符串.
*
*
*
* - 如果不是字符串,返回 false
*
* - 如果是字符串,以"["符号开头,"]"符号结尾的时候,返回 false
* - 如果是字符串,以"{"符号开头,"}"符号结尾的时候,返回 false
*
* - 其他, 返回 true
*
*
.
*
* @param obj
* the obj
* @return true, if is common string
* @since 1.14.0
*/
public static boolean isCommonString(Object obj){
if (!ClassUtil.isInstance(obj, String.class)){
return false;
}
//---------------------------------------------------------------
String str = (String) obj;
if (str.startsWith(OBJECT_START) && str.endsWith(OBJECT_END)){// [] 格式的字符串
return false;
}
if (str.startsWith(ARRAY_START) && str.endsWith(ARRAY_END)){// {} 格式的字符串
return false;
}
return true;
}
/**
* 是否是 {} key-value 格式的字符串.
*
*
*
* - 如果不是字符串,返回 false
* - 如果是null,返回false
* - 如果是字符串,以"{"符号开头,"}"符号结尾的时候,返回 true
* - 其他,返回 false
*
*
.
*
* @param obj
* the obj
* @return 如果是字符串,以"{"符号开头,"}"符号结尾的时候,返回 true
* @since 3.0.0
*/
static boolean isKeyValueJsonString(Object obj){
if (!ClassUtil.isInstance(obj, String.class)){
return false;
}
if (null == obj){
return false;
}
//---------------------------------------------------------------
String str = (String) obj;
return str.startsWith(ToStringUtil.ARRAY_START) && str.endsWith(ToStringUtil.ARRAY_END);
}
// [end]
//---------------------------------------------------------------
/**
* 将 obj转成 {@link JSONArray}.
*
* @param obj
* Accepts JSON formatted strings, arrays, Collections and Enums.
* @param useJsonConfig
* 如果是null,将使用 {@link #DEFAULT_JSON_CONFIG_INSTANCE}
* @return the JSON array
*/
static JSONArray toJSONArray(Object obj,JsonConfig useJsonConfig){
return JSONArrayBuilder.build(obj, defaultIfNull(useJsonConfig, DEFAULT_JSON_CONFIG_INSTANCE));
}
//---------------------------------------------------------------
//toJSONObject
/**
* 将 object转成 {@link JSONObject}.
*
* @param object
* 可以是 null,{@link JSONObject},{@link org.apache.commons.beanutils.DynaBean} ,{@link JSONTokener},
* {@link Map},{@link String},JavaBeans
* @param useJsonConfig
* 如果是null,将使用 {@link #DEFAULT_JSON_CONFIG_INSTANCE}
* @return the JSON object
*/
static JSONObject toJSONObject(Object object,JsonConfig useJsonConfig){
return JSONObjectBuilder.build(object, defaultIfNull(useJsonConfig, DEFAULT_JSON_CONFIG_INSTANCE));
}
//---------------------------------------------------------------
/**
* 是否允许被json format的类型.
*
* 如果是以下类型是被允许的:
*
*
* - {@link ClassUtils#isPrimitiveOrWrapper(Class)}
* - {@link String}
* - {@link ObjectUtil#isArray(Object)}
* - {@link ClassUtil#isInstanceAnyClass(Object, Class...)}
*
*
*
* @param
* the value type
* @param value
* the value
* @param allowClassTypes
* the allow class types
* @return true, if checks if is allow format type
*/
static boolean isAllowFormatType(V value,Class...allowClassTypes){
if (null == value){//null 是可以 format的
return true;
}
//---------------------------------------------------------------
Class klassClass = value.getClass();
return ClassUtils.isPrimitiveOrWrapper(klassClass) //
|| String.class == klassClass //
|| ObjectUtil.isArray(value)//XXX 数组一般 是可以转换的
|| ClassUtil.isInstanceAnyClass(value, allowClassTypes)//
;
}
}