jsonutils.java

一个extjs编写的代码

package anni.json;

import java.io.PrintWriter;

import java.lang.reflect.*;

import java.text.SimpleDateFormat;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;


public class JsonUtils {
    private String inputDatePattern = "";
    private String outputDatePattern = "";

    public JsonUtils() {
        this("yyyy-MM-dd'T'HH:mm:ss", "yyyy-MM-dd'T'HH:mm:ss");
    }

    public JsonUtils(String inputDatePattern, String outputDatePattern) {
        this.inputDatePattern = inputDatePattern;
        this.outputDatePattern = outputDatePattern;
    }

    public <T> T json2Bean(String data, Class<T> clazz) {
        try {
            return json2Bean(data, clazz.newInstance());
        } catch (Exception ex) {
            System.err.println(ex);

            return null;
        }
    }

    public <T> T json2Bean(JsonObject jsonObject, Class<T> clazz) {
        try {
            return json2Bean(jsonObject, clazz.newInstance());
        } catch (Exception ex) {
            System.err.println(ex);

            return null;
        }
    }

    public <T> T json2Bean(String data, T bean) {
        Json json = this.parse(data);

        if (json instanceof JsonObject) {
            JsonObject jsonObject = (JsonObject) json;

            return json2Bean(jsonObject, bean);
        }

        return bean;
    }

    public <T> T json2Bean(JsonObject jsonObject, T bean) {
        for (Method m : bean.getClass().getDeclaredMethods()) {
            String name = m.getName();
            Class[] types = m.getParameterTypes();

            try {
                if (name.startsWith("set") && (types.length == 1)) {
                    Class type = types[0];

                    if (type.equals(byte.class) || type.equals(Byte.class)) {
                        byte value = jsonObject.getByte(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(short.class)
                            || type.equals(Short.class)) {
                        short value = jsonObject.getShort(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(int.class)
                            || type.equals(Integer.class)) {
                        int value = jsonObject.getInt(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(long.class)
                            || type.equals(Long.class)) {
                        long value = jsonObject.getLong(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(float.class)
                            || type.equals(Float.class)) {
                        float value = jsonObject.getFloat(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(double.class)
                            || type.equals(Double.class)) {
                        double value = jsonObject.getDouble(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(char.class)
                            || type.equals(Character.class)) {
                        char value = jsonObject.getChar(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(boolean.class)
                            || type.equals(Boolean.class)) {
                        boolean value = jsonObject.getBoolean(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(String.class)) {
                        String value = jsonObject.getString(m2f(name));

                        m.invoke(bean, value);
                    } else if (type.equals(Date.class)) {
                        Date value = jsonObject.getDate(m2f(name));

                        m.invoke(bean, value);
                    }
                }
            } catch (Exception ex) {
                System.err.println(ex);
            }
        }

        return bean;
    }

    public <T> List<T> json2Array(String data, Class<T> clazz) {
        Json json = this.parse(data);

        List<T> list = new ArrayList<T>();

        if (json instanceof JsonArray) {
            for (Json item : (JsonArray) json) {
                if (item instanceof JsonObject) {
                    JsonObject jsonObject = (JsonObject) item;

                    list.add(json2Bean(jsonObject, clazz));
                }
            }
        } else {
            return list;
        }

        return list;
    }

    private String m2f(String methodName) {
        String fieldName = methodName.substring(3, 4).toLowerCase()
            + methodName.substring(4);

        return fieldName;
    }

    public String bean2Json(Object bean) {
        if (bean instanceof Collection) {
            return bean2JsonArray((Collection) bean);
        } else {
            return bean2JsonObject(bean);
        }
    }

    public void write(Object bean, PrintWriter out) {
        out.print(bean2Json(bean));
        out.flush();
    }

    private String bean2JsonArray(Collection collection) {
        StringBuffer buff = new StringBuffer();
        buff.append("[");

        for (Object o : collection) {
            if (o instanceof Collection) {
                buff.append(bean2JsonArray((Collection) o));
            } else {
                buff.append(bean2JsonObject(o));
            }

            buff.append(",");
        }

        if (buff.length() > 1) {
            buff.deleteCharAt(buff.length() - 1);
        }

        buff.append("]");

        return buff.toString();
    }

    private String bean2JsonObject(Object o) {
        if (o == null) {
            return null;
        }

        StringBuffer buff = new StringBuffer();
        buff.append("{");

        Class clazz = o.getClass();

        if (clazz.equals(String.class)) {
            return "\"" + formatString(o) + "\"";
        } else if (isNumOrBool(clazz)) {
            return o.toString();
        } else {
            for (Method m : clazz.getDeclaredMethods()) {
                String name = m.getName();
                Class[] types = m.getParameterTypes();

                if (name.startsWith("get") && (types.length == 0)) {
                    buff.append("\"").append(m2f(name)).append("\":");

                    try {
                        Object returnValue = m.invoke(o, null);
                        Class type = m.getReturnType();

                        if (returnValue == null) {
                            buff.append("null");
                        } else if (isNumOrBool(type)) {
                            buff.append(returnValue.toString());
                        } else if (returnValue instanceof Collection) {
                            buff.append(bean2JsonArray(
                                    (Collection) returnValue));
                        } else if (type.equals(String.class)) {
                            buff.append("\"")
                                .append(formatString(returnValue))
                                .append("\"");
                        } else if (type.equals(Date.class)) {
                            buff.append("\"")
                                .append(new SimpleDateFormat(
                                    outputDatePattern).format(
                                    (Date) returnValue)).append("\"");
                        } else {
                            buff.append(bean2JsonObject(returnValue));
                        }
                    } catch (Exception ex) {
                        System.err.println(ex);
                        buff.append("null");
                    }

                    buff.append(",");
                }
            }
        }

        if (buff.length() > 1) {
            buff.deleteCharAt(buff.length() - 1);
        }

        buff.append("}");

        return buff.toString();
    }

    private String formatString(Object obj) {
        if (obj == null) {
            return "null";
        } else {
            return obj.toString().replaceAll("\\\\", "\\\\\\\\")
                      .replaceAll("'", "\\\\'").replaceAll("\\\"", "\\\\\"");
        }
    }

    private boolean isNumOrBool(Class clazz) {
        return isNumber(clazz) || isBoolean(clazz);
    }

    private boolean isNumber(Class type) {
        return type.equals(byte.class) || type.equals(Byte.class)
        || type.equals(short.class) || type.equals(Short.class)
        || type.equals(int.class) || type.equals(Integer.class)
        || type.equals(long.class) || type.equals(Long.class)
        || type.equals(float.class) || type.equals(Float.class)
        || type.equals(double.class) || type.equals(Double.class);
    }

    private boolean isBoolean(Class type) {
        return type.equals(boolean.class) || type.equals(Boolean.class);
    }

    // ====================================================
    // parse
    public Json parse(String data) {
        String value = data.trim();
        char c = value.charAt(0);

        if (c == '{') {
            return parseObject(value, 0);
        } else if (c == '[') {
            return parseArray(value, 0);
        }

        return null;
    }

    public JsonObject parseObject(String data, int start) {
        //
        JsonObject jsonObject = null;
        boolean isKey = true;