Benefits of Android Json

Import java. lang. reflect. Method;
Import java. util. Collection;
Import java. util. Map;
Import java. util. Set;
Public final class JsonUtil
{
/**
* Encapsulate an object in JSON format
*
* @ Param o
* Object
* @ Return JSON format
*/
@ SuppressWarnings ("unchecked ")
Public static String toJson (final Object o)
{
If (o = null)
{
Return "null ";
}
If (o instanceof String) // String
{
Return string2Json (String) o );
}
If (o instanceof Boolean) // Boolean
{
Return boolean2Json (Boolean) o );
}
If (o instanceof Number) // Number
{
Return number2Json (Number) o );
}
If (o instanceof Map) // Map
{
Return map2Json (Map <String, Object>) o );
}
If (o instanceof Collection) // List Set
{
Return collection2Json (Collection) o );
}
If (o instanceof Object []) // Object Array
{
Return array2Json (Object []) o );
}
If (o instanceof int []) // array of Basic Types
{
Return intArray2Json (int []) o );
}
If (o instanceof boolean []) // basic type array
{
Return booleanArray2Json (boolean []) o );
}
If (o instanceof long []) // basic type array
{
Return longArray2Json (long []) o );
}
If (o instanceof float []) // basic type array
{
Return floatArray2Json (float []) o );
}
If (o instanceof double []) // basic type array
{
Return doubleArray2Json (double []) o );
}
If (o instanceof short []) // array of Basic Types
{
Return shortArray2Json (short []) o );
}
If (o instanceof byte []) // array of Basic Types
{
Return byteArray2Json (byte []) o );
}
If (o instanceof Object) // The end Object
{
Return object2Json (o );
}
Throw new RuntimeException ("unsupported type:" + o. getClass (). getName ());
}
/**
* Encode a String object in JSON format. You only need to process special characters.
*
* @ Param s
* String object
* @ Return JSON format
*/
Static String string2Json (final String s)
{
Final StringBuilder sb = new StringBuilder (s. length () + 20 );
Sb. append ('\"');
For (int I = 0; I <s. length (); I ++)
{
Final char c = s. charAt (I );
Switch (c)
{
Case '\"':
Sb. append ("\\\"");
Break;
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;
Default:
Sb. append (c );
}
}
Sb. append ('\"');
Return sb. toString ();
}
/**
* Indicates the Number in JSON format.
*
* @ Param number
* Number
* @ Return JSON format
*/
Static String number2Json (final Number number)
{
Return number. toString ();
}
/**
* Boolean is represented in JSON format.
*
* @ Param bool
* Boolean
* @ Return JSON format
*/
Static String boolean2Json (final Boolean bool)
{
Return bool. toString ();
}
/**
* Encode the Collection into JSON format (List, Set)
*
* @ Param c
* @ Return
*/
Static String collection2Json (final Collection <Object> c)
{
Final Object [] arrObj = c. toArray ();
Return toJson (arrObj );
}
/**
* Encode Map <String, Object> In JSON format
*
* @ Param map
* @ Return
*/
Static String map2Json (final Map <String, Object> map)
{
If (map. isEmpty ())
{
Return "{}";
}
Final StringBuilder sb = new StringBuilder (map. size () <4); // 4 th power
Sb. append ('{');
Final Set <String> keys = map. keySet ();
For (final String key: keys)
{
Final Object value = map. get (key );
Sb. append ('\"');
Sb. append (key); // cannot contain special characters
Sb. append ('\"');
Sb. append (':');
Sb. append (toJson (value); // The object referenced cyclically will lead to infinite Recursion
Sb. append (',');
}
// Change the last ',' '}':
Sb. setCharAt (sb. length ()-1 ,'}');
Return sb. toString ();
}
/**
* Encode arrays in JSON format
*
* @ Param array
* Array
* @ Return JSON format
*/
Static String array2Json (final Object [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4); // 4 Power
Sb. append ('[');
For (final Object o: array)
{
Sb. append (toJson (o ));
Sb. append (',');
}
// Change the last ',' to ']':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String intArray2Json (final int [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final int o: array)
{
Sb. append (Integer. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String longArray2Json (final long [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final long o: array)
{
Sb. append (Long. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String booleanArray2Json (final boolean [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final boolean o: array)
{
Sb. append (Boolean. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String floatArray2Json (final float [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final float o: array)
{
Sb. append (Float. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String doubleArray2Json (final double [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final double o: array)
{
Sb. append (Double. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String shortArray2Json (final short [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final short o: array)
{
Sb. append (Short. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Static String byteArray2Json (final byte [] array)
{
If (array. length = 0)
{
Return "[]";
}
Final StringBuilder sb = new StringBuilder (array. length <4 );
Sb. append ('[');
For (final byte o: array)
{
Sb. append (Byte. toString (o ));
Sb. append (',');
}
// Set last', 'to'] ':
Sb. setCharAt (sb. length ()-1, ']');
Return sb. toString ();
}
Public static String object2Json (final Object bean)
{
// Data check
If (bean = null)
{
Return "{}";
}
Final Method [] methods = bean. getClass (). getMethods (); // Method Array
Final StringBuilder sb = new StringBuilder (methods. length <4); // 4 Power
Sb. append ('{');
For (final Method method: methods)
{
Try
{
Final String name = method. getName ();
String key = "";
If (name. startsWith ("get "))
{
Key = name. substring (3 );
// Prevents endless Loops
Final String [] arrs =
{"Class "};
Boolean bl = false;
For (final String s: arrs)
{
If (s. equals (key ))
{
Bl = true;
Continue;
}
}
If (bl)
{
Continue; // prevents endless Loops
}
}
Else if (name. startsWith ("is "))
{
Key = name. substring (2 );
}
If (key. length ()> 0 & Character. isUpperCase (key. charAt (0) & method. getParameterTypes (). length = 0)
{
If (key. length () = 1)
{
Key = key. toLowerCase ();
}
Else if (! Character. isUpperCase (key. charAt (1 )))
{
Key = key. substring (0, 1). toLowerCase () + key. substring (1 );
}
Final Object elementObj = method. invoke (bean );
// System. out. println ("###" + key + ":" + elementObj. toString ());
Sb. append ('\"');
Sb. append (key); // cannot contain special characters
Sb. append ('\"');
Sb. append (':');
Sb. append (toJson (elementObj); // The object referenced cyclically will lead to infinite Recursion
Sb. append (',');
}
}
Catch (final Exception e)
{
// E. getMessage ();
Throw new RuntimeException ("exception when bean is encapsulated into JSON format:" + e. getMessage (), e );
}
}
If (sb. length () = 1)
{
Return bean. toString ();
}
Else
{
Sb. setCharAt (sb. length ()-1 ,'}');
Return sb. toString ();
}
}
Private JsonUtil ()
{
}
}

Author: Feng jingbao