其他格式的数据转化为 json格式的方法

转自：http://blog.csdn.net/liuzhengkang/article/details/2987588

需要使用json格式数据的时候，将其他格式的数据转化为json格式的方法：

import java.beans.IntrospectionException;

import java.beans.Introspector;

import java.beans.PropertyDescriptor;

import java.math.BigDecimal;

import java.math.BigInteger;

import java.text.SimpleDateFormat;

import java.util.Date;

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 Date) {

SimpleDateFormat simpleDateFormat = new SimpleDateFormat(

"yyyy-MM-dd HH:mm:ss");

json.append("\"").append(

string2json(simpleDateFormat.format((Date) obj))).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();

}

}