json格式与java类对象相互转换

package com.jackson.bean; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Set; import org.codehaus.jackson.map.ObjectMapper; public class Test { public static ObjectMapper objectMapper = new ObjectMapper(); public static void main(String[] args) { jsontolist(); } public static void jsontomap() { try { String json = "{\"A\":{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},\"B\":{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}}"; // String json = "{\"success\":true,\"A\":{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},\"B\":{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}}"; Map<String, Map<String, Object>> maps = objectMapper.readValue( json, Map.class); System.out.println(maps.size()); Set<String> key = maps.keySet(); Iterator<String> iter = key.iterator(); while (iter.hasNext()) { String field = iter.next(); System.out.println(field + ":" + maps.get(field)); } } catch (Exception e) { e.printStackTrace(); } } public static void jsontolist() { try { String json = "[{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}]"; List<LinkedHashMap<String, Object>> list = objectMapper.readValue(json, List.class); System.out.println(list.size()); for (int i = 0; i < list.size(); i++) { Map<String, Object> map = list.get(i); Set<String> set = map.keySet(); Bean bean = new Bean(); bean.setAddress((String) map.get("address")); bean.setEmail((String) map.get("email")); bean.setId(Integer.parseInt(map.get("id")+"")); bean.setName((String) map.get("name")); System.out.println(bean); // for (Iterator<String> it = set.iterator(); it.hasNext();) { // String key = it.next(); // System.out.println(key + ":" + map.get(key)); // } } } catch (Exception e) { e.printStackTrace(); } } public static void jsontoarr() { try { String json = "[{\"address\": \"address2\",\"name\":\"haha2\",\"id\":2,\"email\":\"email2\"},{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}]"; Bean[] arr = objectMapper.readValue(json, Bean[].class); System.out.println(arr.length); for (int i = 0; i < arr.length; i++) { Bean bean = arr[i]; System.out.println(bean); } } catch (Exception e) { e.printStackTrace(); } } public static void jsontobean() { try { String json = "{\"address\":\"address\",\"name\":\"haha\",\"id\":1,\"email\":\"email\"}"; Bean acc = objectMapper.readValue(json, Bean.class); System.out.println(acc.getName()); System.out.println(acc); } catch (Exception e) { e.printStackTrace(); } } }