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转: archie2010
高效的JSON处理器
JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。
易于人阅读和编写。同时也易于机器解析和生成
JSON-lib官网:http://json-lib.sourceforge.net/
Jackson官网:http://jackson.codehaus.org/
号称性能最快的JSON处理器Jackson远高于JSON_lib
转化json字符串:
- /** * 使用Jackson生成json格式字符串 *
- * @author archie2010 since 2011-4-26下午05:59:46
- */public class JacksonTest {
- private static JsonGenerator jsonGenerator = null;
- private static ObjectMapper objectMapper = null;
- private static User user = null;
- /**
- * 转化实体为json字符串
- * @throws IOException
- */ 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);
- }
- /**
- * 转化Map为json字符串
- * @throws JsonGenerationException
- * @throws JsonMappingException
- * @throws IOException
- */ public static void writeMap2Json() throws JsonGenerationException, JsonMappingException, IOException{
- System.out.println("转化Map为字符串--------");
- Map<String, Object> map=new HashMap<String, Object>();
- map.put("uname", user.getUname());
- map.put("upwd", user.getUpwd());
- map.put("USER", user);
- objectMapper.writeValue(System.out, map);
- }
- /**
- * 转化List为json字符串
- * @throws IOException
- * @throws JsonMappingException
- * @throws JsonGenerationException
- */ 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);
- objectMapper.writeValue(System.out, userList);
- }
- public static void main(String[] args) {
- user = new User();
- user.setUid(5);
- user.setUname("tom");
- user.setUpwd("123");
- user.setNumber(3.44);
- objectMapper = new ObjectMapper();
- try {
- jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(System.out, JsonEncoding.UTF8);
- //writeEntity2Json();
- //writeMap2Json();
- writeList2Json();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }}[{"number":3.44,"uname":"tom","upwd":"123","uid":5},{"number":0.0,"uname":"archie","upwd":"123","uid":10}]
复制代码 输出到浏览器端:
- StringWriter writer = new StringWriter();
- ObjectMapper mapper = new ObjectMapper();
- try {
- mapper.writeValue(writer, hMap);
- } catch (JsonGenerationException e) {
- e.printStackTrace();
- } catch (JsonMappingException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }
- response.setContentType("text/html;charset=UTF-8");
- PrintWriter out= response.getWriter();out.print(writer.toString());
复制代码 |
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