package com.bbs.utils.json;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.node.JsonNodeFactory;

public class JacksonTest {
 private static JsonGenerator jsonGenerator = null;
 private static ObjectMapper objectMapper = null;
 private static User user = null;

 public static void writeEntity2Json() throws IOException {
  System.out.println("使用JsonGenerator转化实体为json串-------------");
  // writeObject可以转换java对象，eg:JavaBean/Map/List/Array等
  jsonGenerator.writeObject(user);
  System.out.println();
  System.out.println("使用ObjectMapper-----------");
  // writeValue具有和writeObject相同的功能
  objectMapper.writeValue(System.out, user);
 }

 public static void writeList2Json() throws IOException {
  List<User> userList = new ArrayList<User>();
  userList.add(user);
  User u = new User();
  u.setUid(10);
  u.setUname("archie");
  u.setUpwd("123");
  userList.add(u);
  objectMapper.writeValue(System.out, userList);
 }

 public static void writeMap2Json() {
  try {
   Map<String, Object> map = new HashMap<String, Object>();
   User u = new User();
   u.setUid(10);
   u.setUname("archie");
   u.setUpwd("123");
   map.put("uid", u.getUid());
   map.put("uname", u.getUname());
   map.put("upwd", u.getUpwd());
   System.out.println("jsonGenerator");
   jsonGenerator.writeObject(map);
   objectMapper.writeValue(System.out, map);
  } catch (IOException e) {
   e.printStackTrace();
  }
 }

 public static void writeOthersJSON() {
  try {
   String[] arr = { "a", "b", "c" };
   System.out.println("jsonGenerator");
   String str = "hello world jackson!";
   // byte
   jsonGenerator.writeBinary(str.getBytes());
   // boolean
   jsonGenerator.writeBoolean(true);
   // null
   jsonGenerator.writeNull();
   // float
   jsonGenerator.writeNumber(2.2f);
   // char
   jsonGenerator.writeRaw("c");
   // String
   jsonGenerator.writeRaw(str, 5, 10);
   // String
   jsonGenerator.writeRawValue(str, 5, 5);
   // String
   jsonGenerator.writeString(str);
   jsonGenerator.writeTree(JsonNodeFactory.instance.POJONode(str));
   System.out.println();
   // Object
   jsonGenerator.writeStartObject();// {
   jsonGenerator.writeObjectFieldStart("user");// user:
   jsonGenerator.writeStringField("name", "jackson");// name:jackson
   jsonGenerator.writeBooleanField("sex", true);// sex:true
   jsonGenerator.writeNumberField("age", 22);// age:22
   jsonGenerator.writeEndObject();
   jsonGenerator.writeArrayFieldStart("infos");// infos:[
   jsonGenerator.writeNumber(22);// 22
   jsonGenerator.writeString("this is array");// this is array
   jsonGenerator.writeEndArray();// ]
   jsonGenerator.writeEndObject();// }
   User u = new User();
   user.setUid(5);
   user.setUname("tom");
   user.setUpwd("123");
   user.setNumber(3.44);
   // complex Object
   jsonGenerator.writeStartObject();// {
   jsonGenerator.writeObjectField("uid", u);// user:{bean}
   jsonGenerator.writeObjectField("infos", arr);// infos:[array]
   jsonGenerator.writeEndObject();// }
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 /**
  * JSON字符串转换为对象
  */
 public static void readJson2Entity() {
  String json = "{\"uid\":5,\"uname\":\"tom\",\"number\":3.44,\"upwd\":\"123\"}";
  try {
   User acc = objectMapper.readValue(json, User.class);
   System.out.println(acc.getUid());
   System.out.println(acc);
  } catch (JsonParseException e) {
   e.printStackTrace();
  } catch (JsonMappingException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.p