json解析和封装Util（很实用）

import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Map;
import java.util.Set;

public final class JsonUtil 
{ 

        /** 
         * 把对象封装为JSON格式 
         * 
         * @param o 
         *            对象 
         * @return JSON格式 
         */ 
        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[]) //对象数组 
                { 
                        return array2Json((Object[]) o); 
                } 

                if (o instanceof int[])//基本类型数组 
                { 
                        return intArray2Json((int[]) o); 
                } 
                if (o instanceof boolean[])//基本类型数组 
                { 
                        return booleanArray2Json((boolean[]) o); 
                } 
                if (o instanceof long[])//基本类型数组 
                { 
                        return longArray2Json((long[]) o); 
                } 
                if (o instanceof float[])//基本类型数组 
                { 
                        return floatArray2Json((float[]) o); 
                } 
                if (o instanceof double[])//基本类型数组 
                { 
                        return doubleArray2Json((double[]) o); 
                } 
                if (o instanceof short[])//基本类型数组 
                { 
                        return shortArray2Json((short[]) o); 
                } 
                if (o instanceof byte[])//基本类型数组 
                { 
                        return byteArray2Json((byte[]) o); 
                } 
                if (o instanceof Object) //保底收尾对象 
                { 
                        return object2Json(o); 
                } 

                throw new RuntimeException("不支持的类型: " + o.getClass().getName());
         } 

        /** 
         * 将 String 对象编码为 JSON格式，只需处理好特殊字符 
         * 
         * @param s 
         *            String 对象 
         * @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(); 
        } 

        /** 
         * 将 Number 表示为 JSON格式 
         * 
         * @param number 
         *            Number 
         * @return JSON格式 
         */ 
        static String number2Json(final Number number) 
        { 
                return number.toString(); 
        } 

        /** 
         * 将 Boolean 表示为 JSON格式 
         * 
         * @param bool 
         *            Boolean 
         * @return JSON格式 
         */ 
        static String boolean2Json(final Boolean bool) 
        { 
                return bool.toString(); 
        } 

        /** 
         * 将 Collection 编码为 JSON 格式 (List,Set) 
         * 
         * @param c 
         * @return 
         */ 
        static String collection2Json(final Collection<Object> c) 
        { 
                final Object[] arrObj = c.toArray(); 
                return toJson(arrObj); 
        } 

        /** 
         * 将 Map<String, Object> 编码为 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)); //循环引用的对象会引发无限递归 
                        sb.append(','); 
                } 
                // 将最后的 ',' 变为 '}': 
                sb.setCharAt(sb.length() - 1, '}'); 
                return sb.toString(); 
        } 

        /** 
         * 将数组编码为 JSON 格式 
         * 
         * @param array 
         *            数组 
         * @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(','); 
                } 
                // 将最后添加的 ',' 变为 ']': 
                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) 
        { 
                //数据检查 
                if (bean == null) 
                { 
                        return "{}"; 
                } 
                final Method[] methods = bean.getClass().getMethods(); //方法数组 
                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); 

                                        //防死循环 
                                        final String[] arrs = 
                                        { "Class" }; 
                                        boolean bl = false; 
                                        for (final String s : arrs) 
                                        { 
                                                if (s.equals(key)) 
                                                { 
                                                        bl = true; 
                                                        continue; 
                                                } 
                                        } 
                                        if (bl) 
                                        { 
                                                continue; //防死循环 
                                        } 
                                } 
                                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)); //循环引用的对象会引发无限递归
                                         sb.append(','); 
                                } 
                        } 
                        catch (final Exception e) 
                        { 
                                //e.getMessage(); 
                                throw new RuntimeException("在将bean封装成JSON格式时异常：" + e.getMessage(), e);
                         } 
                } 
                if (sb.length() == 1) 
                { 
                        return bean.toString(); 
                } 
                else 
                { 
                        sb.setCharAt(sb.length() - 1, '}'); 
                        return sb.toString(); 
                } 
        } 

        private JsonUtil() 
        { 
        } 
} 

 

测试类：


public class TestObject2Json {
 public static void main(String[] args) {
  
  Student s=new Student();
  s.setId(1);
  s.setMoney(20);
  s.setName("huahua");
  s.setPwd("123");
  System.out.println(JsonUtil.toJson(s));
 }

}