Android Json的福音

import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
public final class JsonUtil
{
/**
* 把對象封裝為JSON格式
*
* @param o
* 對象
* @return  JSON格式
*/
@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[]) //對象數組
{
return array2Json((Object[]) o);
}
if (o instanceof int[])//基本類型數組
{
return intArray2Json((int[]) o);
}
if (o instanceof boolean[])//基本類型數組
{
return booleanArray2Json((boolean[]) o);
}
if (o instanceof long[])//基本類型數組
{
return longArray2Json((long[]) o);
}
if (o instanceof float[])//基本類型數組
{
return floatArray2Json((float[]) o);
}
if (o instanceof double[])//基本類型數組
{
return doubleArray2Json((double[]) o);
}
if (o instanceof short[])//基本類型數組
{
return shortArray2Json((short[]) o);
}
if (o instanceof byte[])//基本類型數組
{
return byteArray2Json((byte[]) o);
}
if (o instanceof Object) //保底收尾對象
{
return object2Json(o);
}
throw new RuntimeException("不支持的類型: " + o.getClass().getName());
}
/**
* 將 String 對象編碼為 JSON格式,隻需處理好特殊字符
*
* @param s
* String 對象
* @return  JSON格式
*/
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();
}
/**
* 將 Number 表示為 JSON格式
*
* @param number
* Number
* @return  JSON格式
*/
static String number2Json(final Number number)
{
return number.toString();
}
/**
* 將 Boolean 表示為 JSON格式
*
* @param bool
* Boolean
* @return  JSON格式
*/
static String boolean2Json(final Boolean bool)
{
return bool.toString();
}
/**
* 將 Collection 編碼為 JSON 格式 (List,Set)
*
* @param c
* @return
*/
static String collection2Json(final Collection<Object> c)
{
final Object[] arrObj = c.toArray();
return toJson(arrObj);
}
/**
* 將 Map<String, Object> 編碼為 JSON 格式
*
* @param map
* @return
*/
static String map2Json(final Map<String, Object> map)
{
if (map.isEmpty())
{
return "{}";
}
final StringBuilder sb = new StringBuilder(map.size() << 4); //4次方
sb.append('{');
final Set<String> keys = map.keySet();
for (final String key : keys)
{
final Object value = map.get(key);
sb.append('\"');
sb.append(key); //不能包含特殊字符
sb.append('\"');
sb.append(':');
sb.append(toJson(value)); //循環引用的對象會引發無限遞歸
sb.append(',');
}
// 將最後的 ',' 變為 '}':
sb.setCharAt(sb.length() – 1, '}');
return sb.toString();
}
/**
* 將數組編碼為 JSON 格式
*
* @param array
* 數組
* @return  JSON 格式
*/
static String array2Json(final Object[] array)
{
if (array.length == 0)
{
return "[]";
}
final StringBuilder sb = new StringBuilder(array.length << 4); //4次方
sb.append('[');
for (final Object o : array)
{
sb.append(toJson(o));
sb.append(',');
}
// 將最後添加的 ',' 變為 ']':
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)
{
//數據檢查
if (bean == null)
{
return "{}";
}
final Method[] methods = bean.getClass().getMethods(); //方法數組
final StringBuilder sb = new StringBuilder(methods.length << 4); //4次方
sb.append('{');
for (final Method method : methods)
{
try
{
final String name = method.getName();
String key = "";
if (name.startsWith("get"))
{
key = name.substring(3);
//防死循環
final String[] arrs =
{ "Class" };
boolean bl = false;
for (final String s : arrs)
{
if (s.equals(key))
{
bl = true;
continue;
}
}
if (bl)
{
continue; //防死循環
}
}
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); //不能包含特殊字符
sb.append('\"');
sb.append(':');
sb.append(toJson(elementObj)); //循環引用的對象會引發無限遞歸
sb.append(',');
}
}
catch (final Exception e)
{
//e.getMessage();
throw new RuntimeException("在將bean封裝成JSON格式時異常:" + e.getMessage(), e);
}
}
if (sb.length() == 1)
{
return bean.toString();
}
else
{
sb.setCharAt(sb.length() – 1, '}');
return sb.toString();
}
}
private JsonUtil()
{
}
}

 作者:馮京寶

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