package org.arong.util;
import java.beans.Introspector;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 封装了将各种对象、集合转换成json字符串的方法
* @author arong
* @since 1.0.10
*/
public final class JsonUtil {
/**
* 将javabean对象转换为json字符串
*
* @param bean
* 带着数据的javabean对象
* @param excludes
* 对javabean的一些字段排除
*
* @return 符合json规范的字符串
*/
public static <T> String bean2Json(T bean, String... excludes) {
StringBuilder sb = new StringBuilder("{");
try {
@SuppressWarnings("unchecked")
Class<T> clazz = (Class<T>) bean.getClass();
Method[] methods = clazz.getDeclaredMethods();
String methodName = null;
String name = null;
Object value = null;
for (int i = 0; i < methods.length; i++) {
methodName = methods[i].getName();
if (methodName.startsWith("get") || methodName.startsWith("is")) {
int len = methodName.startsWith("get") ? 3 : 2;
// 通过Introspector类的静态方法decapitalize获取每个get方法对应的属性名
name = Introspector.decapitalize(methodName.substring(len,
methodName.length()));
// 排除字段
if (!Arrays.asList(excludes).contains(name)) {
// 执行get方法，获得返回值
value = methods[i].invoke(bean);
if (value == null)
value = "null";
executeAppend(sb, "{", name, value);
}
}
}
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
sb.append("}");
return sb.toString();
}
/**
* 将一个带着数据的javabean集合对象转化成符合JSON规范的字符串。<br>
* 返回的json字符串 键/值 都是String类型，如果某个属性没有数据则为"null"，<br>
* 如果某个属性为另外的javabean，则返回Object.toString()生成的值。
* <p>
* 此方法中要求javabean必须符合命名规范，生成的json键与javabean中的属性名一致。
* </p>
*
* @param list
* 带着数据的javabean集合
* @param excludes
* 对javabean的一些字段排除
* @return 符合json规范的字符串
* @author arong
* @since 1.0.2
*/
public static <T> String beanList2Json(List<T> list, String... excludes) {
// 定义json的可变字符串
StringBuilder json = new StringBuilder("[");
T bean = null;
for (int i = 0; i < list.size(); i++) {
// 获取bean对象
bean = list.get(i);
json.append((i != 0 ? "," : "") + bean2Json(bean, excludes));
}
json.append("]");
return json.toString();
}
/**
* 将一个javabean集合转化为json字符串<br>
* 此方法生成的字符串长度比beanList2Json方法要短<br>
* 格式：{字段1:[值,值,值],字段2:[值,值,值]……}
*
* @param list
* 带着数据的javabean集合
* @param excludes
* 对javabean的一些字段排除
* @return
*/
@SuppressWarnings("unchecked")
public static <T> String beanList2Json2(List<T> list, String... excludes) {
// 定义json的可变字符串
StringBuilder json = new StringBuilder("{");
StringBuilder sb = null;
// bean方法名
String methodName = null;
// bean属性名
String name = null;
// bean属性值
Object value = null;
T bean = null;
Integer length = list.size();
if (length > 0) {
Class<T> clazz = (Class<T>) list.get(0).getClass();
Method[] methods = clazz.getDeclaredMethods();
for (int i = 0; i < methods.length; i++) {
// 获取方法名
methodName = methods[i].getName();
if (methodName.startsWith("get") || methodName.startsWith("is")) {
int len = methodName.startsWith("get") ? 3 : 2;
// 通过Introspector类的静态方法decapitalize获取每个get方法对应的属性名
name = Introspector.decapitalize(methodName.substring(len,
methodName.length()));
// 排除字段
if (!Arrays.asList(excludes).contains(name)) {
sb = new StringBuilder(name + ":[");
for (int j = 0; j < length; j++) {
// 获取bean对象
bean = list.get(j);
// 定义一个可变字符串，用于构造js数组[]中的内容
try {
// 执行get方法，获得返回值
value = methods[i].invoke(bean);
if (value == null)
value = "null";
executeAppend2(sb, name + ":[", value);
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
sb.append("]");
if (json.toString().equals("{")) {
json.append(sb.toString());
} else {
json.append("," + sb.toString());
}
}
}
}
}
json.append("}");
return json.toString();
}
/**
* 将一个map对象转换为json字符串
*
* @param map
* map对象
* @return
*/
public static String map2Json(Map<Object, Object> map) {
List<Map<Object, Object>> list = new ArrayList<Map<Object, Object>>();
list.add(map);
return mapList2Json(list);
}
/**
* 将一个Map<Object, Object>的集合转换为json字符串
*
* @param list
* Map<Object, Object>的集合
* @return
*/
@SuppressWarnings({ "unchecked"})
public static String mapList2Json(List<Map<Object, Object>> list) {
// 定义json的可变字符串
StringBuilder json = new StringBuilder("[");
// 根据json的格式，{}对的个数为集合的长度，每个{}对代表一个集合中的一个map对象
// map值
Object value = null;
StringBuilder sb = null;
Map<Object, Object> map = null;
for (int i = 0; i < list.size(); i++) {
// 定义一个可变字符串，用于构造{}中的内容
sb = new StringBuilder("{");
map = list.get(i);
Set<Object> set = map.keySet();
for (Object name : set) {
value = map.get(name);
if (value == null)
value = "null";
//如果还包含有集合，则递归
if(value instanceof List){
executeAppend(sb, "{", name.toString(), mapList2Json((List)value));
}else{
executeAppend(sb, "{", name.toString(), value);
}
}
// 拼接成完整的{}对
sb.append("}");
if (json.toString().equals("[")) {
json.append(sb.toString());
} else {
json.append("," + sb.toString());
}
}
json.append("]");
return json.toString();
}
/**
* 将一个数组转换为json字符串，key为数组的索引，从0开始
*
* @param array
* 数组对象
* @return
*/
public static String array2Json(Object[] array) {
List<Object[]> list = new ArrayList<Object[]>();
list.add(array);
return arrayList2Json(list);
}
/**
* 将一个数组集合转换为json字符串
*
* @param list
* 数组集合
* @return
*/
public static String arrayList2Json(List<Object[]> list) {
// 定义json的可变字符串
StringBuilder json = new StringBuilder("[");
// 根据json的格式，{}对的个数为集合的长度，每个{}对代表一个集合中的一个array对象
// map值
Object value = null;
StringBuilder sb = null;
Object[] array = null;
for (int i = 0; i < list.size(); i++) {
// 定义一个可变字符串，用于构造{}中的内容
sb = new StringBuilder("{");
array = list.get(i);
for (int j = 0; j < array.length; j++) {
value = array[j];
if (value == null)
value = "null";
executeAppend(sb, "{", j + "", value);
}
// 拼接成完整的{}对
sb.append("}");
if (json.toString().equals("[")) {
json.append(sb.toString());
} else {
json.append("," + sb.toString());
}
}
json.append("]");
return json.toString();
}
/**
* 内部方法，用于StringBuilder的json字符串追加
*
* @param sb
* StringBuilder对象
* @param prefix
* StringBuilder对象初始的值
* @param name
* 键
* @param value
* 值
*/
private static void executeAppend(StringBuilder sb, String prefix,
String name, Object value) {
if (sb.toString().equals(prefix)) {
if (value instanceof java.lang.String
|| value instanceof java.util.Date) {
sb.append(name + ":\'" + stringtoJSON(value.toString()) + "\'");
} else {
sb.append(name + ":" + stringtoJSON(value.toString()));
}
} else {
if (value instanceof java.lang.String
|| value instanceof java.util.Date) {
sb.append("," + name + ":\'" + stringtoJSON(value.toString())
+ "\'");
} else {
sb.append("," + name + ":" + stringtoJSON(value.toString()));
}
}
}
/**
* 内部方法，用于StringBuilder的json字符串追加
*
* @param sb
* @param prefix
* @param value
*/
private static void executeAppend2(StringBuilder sb, String prefix,
Object value) {
if (sb.toString().equals(prefix)) {
if (value instanceof java.lang.String
|| value instanceof java.util.Date) {
sb.append("\"" + stringtoJSON(value.toString()) + "\"");
} else {
sb.append(stringtoJSON(value.toString()));
}
} else {
if (value instanceof java.lang.String
|| value instanceof java.util.Date) {
sb.append("," + "\"" + stringtoJSON(value.toString()) + "\"");
} else {
sb.append("," + stringtoJSON(value.toString()));
}
}
}
/**
* 将一个字符串s转换为能在json中存储而不破坏其格式的字符串
*
* @param s
* @return
*/
public static String stringtoJSON(String s) {
if (s == null) {
return "";
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.length(); i++) {
char ch = s.charAt(i);
switch (ch) {
case '"':
sb.append("\\\"");
break;
case '\\':
sb.append("\\\\");
break;
case '\b':
sb.append("\\b");
break;
case '\f':
sb.append("\\f");
break;
case '\n':
sb.append("\\n");
break;
case '\r':
sb.append("\\r");
break;
case '\t':
sb.append("\\t");
break;
case '/':
sb.append("\\/");
break;
default:
if (ch >= '\u0000' && ch <= '\u001F') {
String ss = Integer.toHexString(ch);
sb.append("\\u");
for (int k = 0; k < 4 - ss.length(); k++) {
sb.append('0');
}
sb.append(ss.toUpperCase());
} else {
sb.append(ch);
}
}
}
return sb.toString();
}
/**
* 用于重写javabean中的toString()方法<br>
* 当一个bean中包含另外一个bean时，则另一个bean中应该重写toString()方法
* @param bean
* @param excludes
* @return
*/
public static String toString(Object bean, String... excludes){
StringBuilder sb = new StringBuilder("{");
Class<?> clazz = bean.getClass();
Method[] methods = clazz.getDeclaredMethods();
String methodName = null;
String name = null;
Object value = null;
Integer len = null;
for (int i = 0; i < methods.length; i++) {
methodName = methods[i].getName();
if(methodName.startsWith("get") || methodName.startsWith("is")){
len = methodName.startsWith("get")?3:2;
name = Introspector.decapitalize(methodName.substring(len, methodName.length()));
//排除字段
if(!Arrays.asList(excludes).contains(name)){
try {
value = methods[i].invoke(bean);
if(value == null)
value = "null";
executeAppend(sb, "{", name, value);
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
}
}
sb.append("}");
return sb.toString();
}
/**
* 简单(不嵌套)json字符串转换为map<br>
* 约定：key必须要有引号,引号为双引号
* @param json
* @return Map
*/
public static Map<String, String> json2Map(String json){
if(json != null && !"".equals(json.trim())){
if('{' == json.charAt(0)){
if('}' == json.charAt(json.length() - 1)){
json = json.substring(2, json.length() - 1);
String[] arr = json.split(",\"");
String[] kv;
Map<String, String> data = new HashMap<String, String>();
for(int i = 0; i < arr.length; i ++){
if(arr[i].trim().indexOf("\":") != -1){
kv = arr[i].trim().split("\":");
if('"' == kv[1].charAt(0) && '"' == kv[1].charAt(kv[1].length() - 1)){
data.put(kv[0], kv[1].substring(1, kv[1].length() - 1));
}else{
data.put(kv[0], kv[1]);
}
}else{
throw new RuntimeException("json格式错误");
}
}
return data;
}else{
throw new RuntimeException("json尾字符不为：}");
}
}else{
throw new RuntimeException("json首字符不为：{");
}
}else{
throw new RuntimeException("json为空");
}
}
/**
* 简单(不嵌套)json字符串转换为javabean<br>
* javabean中的字段有set方法，且字段名与json的key一致
* @param <T>
* @param clazz
* @param json
* @return T
*/
public static <T> T json2bean(Class<T> clazz, String json){
Map<String, String> map = json2Map(json);
T t = null;
try {
t = clazz.newInstance();
if(map != null){
for(String key : map.keySet()){
BeanUtil.setProperty(t, key, new String[]{map.get(key)});
}
}
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return t;
}
/**
* 简单(不嵌套)json数组字符串转换为map集合
* @param json
* @return List<Map<String,String>>
*/
public static List<Map<String, String>> jsonArray2MapList(String json){
if(json != null && !"".equals(json.trim())){
if('[' == json.charAt(0)){
if(']' == json.charAt(json.length() - 1)){
json = json.substring(2, json.length() - 2);
String[] arr = json.split("\\},\\{");
List<Map<String, String>> maps = new ArrayList<Map<String,String>>();
for(int i = 0; i < arr.length; i ++){
maps.add(json2Map("{" + arr[i] + "}"));
}
return maps;
}else{
throw new RuntimeException("json尾字符不为：]");
}
}else{
throw new RuntimeException("json首字符不为：[");
}
}else{
throw new RuntimeException("json为空");
}
}
/**
* 简单(不嵌套)json数组字符串转换为javabean集合
* @param json
* @return List<T>
*/
public static <T> List<T> jsonArray2beanList(Class<T> clazz, String json){
if(json != null && !"".equals(json.trim())){
if('[' == json.charAt(0)){
if(']' == json.charAt(json.length() - 1)){
json = json.substring(2, json.length() - 2);
String[] arr = json.split("\\},\\{");
List<T> beans = new ArrayList<T>();
for(int i = 0; i < arr.length; i ++){
beans.add(json2bean(clazz, "{" + arr[i] + "}"));
}
return beans;
}else{
throw new RuntimeException("json尾字符不为：]");
}
}else{
throw new RuntimeException("json首字符不为：[");
}
}else{
throw new RuntimeException("json为空");
}
}
public static void main(String[] args) {
String json = "{\"name\":\"m0000.jpg\",\"total\":12,\"score\":96.5,\"isCompleted\":false,\"url\":\"http://www.baidu.com/s/77eo9ec5bb/672439-1\"}";
System.out.println(json2Map(json));
/*List<Map<Object, Object>> list = new ArrayList<Map<Object,Object>>();
Map<Object, Object> map = new HashMap<Object, Object>();
map.put("name", "zsr");
map.put("gender", "male");
map.put("age", "18");
map.put("job", "java工程师");
List<Map> in_list = new ArrayList<Map>();
Map map_1 = new HashMap();
map_1.put("er", "1232");
map_1.put("gp", "12342");
map_1.put("lk", "23123");
in_list.add(map_1);
Map map_2 = new HashMap();
map_2.put("er", "1122");
map_2.put("gp", "11342");
map_2.put("lk", "24123");
in_list.add(map_2);
map.put("datas", in_list);
list.add(map);
String sss = mapList2Json(list);
System.out.println(sss);*/
}
}