Java将List,Set,Arrary,String，Object转换为JSON格式

以你之姓@ 2022-06-15 00:14 245阅读 0赞

package util;  
  
  
import java.beans.IntrospectionException;  
  
  
import java.beans.Introspector;  
  
  
import java.beans.PropertyDescriptor;  
  
  
import java.math.BigDecimal;  
import java.math.BigInteger;  
import java.util.List;  
import java.util.Map;  
import java.util.Set;  
import org.apache.commons.logging.Log;  
import org.apache.commons.logging.LogFactory;  
  
  
public class JsonUtil \{  
private static Log log = LogFactory.getLog(JsonUtil.class);  
  
  
public static String object2json(Object obj) \{  
StringBuilder json = new StringBuilder();  
if (obj == null) \{  
json.append("\\"\\"");  
\} else if (obj instanceof String || obj instanceof Integer || obj instanceof Float || obj instanceof Boolean  
|| obj instanceof Short || obj instanceof Double || obj instanceof Long || obj instanceof BigDecimal  
|| obj instanceof BigInteger || obj instanceof Byte) \{  
json.append("\\"").append(string2json(obj.toString())).append("\\"");  
\} else if (obj instanceof Object\[\]) \{  
json.append(array2json((Object\[\]) obj));  
\} else if (obj instanceof List) \{  
json.append(list2json((List<?>) obj));  
\} else if (obj instanceof Map) \{  
json.append(map2json((Map<?, ?>) obj));  
\} else if (obj instanceof Set) \{  
json.append(set2json((Set<?>) obj));  
\} else \{  
json.append(bean2json(obj));  
\}  
return json.toString();  
\}  
  
  
public static String bean2json(Object bean) \{  
StringBuilder json = new StringBuilder();  
json.append("\{");  
PropertyDescriptor\[\] props = null;  
try \{  
props = Introspector.getBeanInfo(bean.getClass(), Object.class).getPropertyDescriptors();  
\} catch (IntrospectionException e) \{  
\}  
if (props != null) \{  
for (int i = 0; i < props.length; i++) \{  
try \{  
String name = object2json(props\[i\].getName());  
String value = object2json(props\[i\].getReadMethod().invoke(bean));  
json.append(name);  
json.append(":");  
json.append(value);  
json.append(",");  
\} catch (Exception e) \{  
\}  
\}  
json.setCharAt(json.length() - 1, '\}');  
\} else \{  
json.append("\}");  
\}  
return json.toString();  
\}  
  
  
public static String list2json(List<?> list) \{  
StringBuilder json = new StringBuilder();  
json.append("\[");  
if (list != null && list.size() > 0) \{  
for (Object obj : list) \{  
json.append(object2json(obj));  
json.append(",");  
\}  
json.setCharAt(json.length() - 1, '\]');  
\} else \{  
json.append("\]");  
\}  
return json.toString();  
\}  
  
  
public static String array2json(Object\[\] array) \{  
StringBuilder json = new StringBuilder();  
json.append("\[");  
if (array != null && array.length > 0) \{  
for (Object obj : array) \{  
json.append(object2json(obj));  
json.append(",");  
\}  
json.setCharAt(json.length() - 1, '\]');  
\} else \{  
json.append("\]");  
\}  
return json.toString();  
\}  
  
  
public static String map2json(Map<?, ?> map) \{  
StringBuilder json = new StringBuilder();  
json.append("\{");  
if (map != null && map.size() > 0) \{  
for (Object key : map.keySet()) \{  
json.append(object2json(key));  
json.append(":");  
json.append(object2json(map.get(key)));  
json.append(",");  
\}  
json.setCharAt(json.length() - 1, '\}');  
\} else \{  
json.append("\}");  
\}  
return json.toString();  
\}  
  
  
public static String set2json(Set<?> set) \{  
StringBuilder json = new StringBuilder();  
json.append("\[");  
if (set != null && set.size() > 0) \{  
for (Object obj : set) \{  
json.append(object2json(obj));  
json.append(",");  
\}  
json.setCharAt(json.length() - 1, '\]');  
\} else \{  
json.append("\]");  
\}  
return json.toString();  
\}  
  
  
public static String string2json(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();  
\}  
\}