jackson与fastjson的使用

jackson与fastjson的使用

jackson

1. 导包

   <dependency>
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-databind</artifactId>
       <version>2.10.1</version>
   </dependency>
   

2. 处理乱码

3. json解析

   //@Controller
   @RestController//不经过视图解析器,return字符串
   public class UserController {
       @RequestMapping("/json1")
       //@ResponseBody//不经过视图解析器,return字符串
       public String json1() throws JsonProcessingException {
           //jackson - ObjectMapper
           ObjectMapper mapper = new ObjectMapper();
           User user = new User("大头儿子", 6, "男");
           String string = mapper.writeValueAsString(user);
           return string;
       }
   
       @RequestMapping("/json2")
       //队列
       public String json2() throws JsonProcessingException {
           ObjectMapper mapper = new ObjectMapper();
           List<User> userList = new ArrayList<User>();
           User user1 = new User("大头儿子", 6, "男");
           User user2 = new User("也是大头儿子", 6, "男");
           User user3 = new User("还是大头儿子", 6, "男");
           User user4 = new User("不是大头儿子", 6, "女");
           userList.add(user1);
           userList.add(user2);
           userList.add(user3);
           userList.add(user4);
           String users = mapper.writeValueAsString(userList);
           return users;
       }
   
       @RequestMapping("/json3")
       //时间
       public String json3() throws JsonProcessingException {
           ObjectMapper mapper = new ObjectMapper();
           Date oridate = new Date();
           //通过java格式化时间
           SimpleDateFormat format = new SimpleDateFormat("yy-MM-dd HH:mm:ss");
           String date = format.format(oridate);
           String obj = mapper.writeValueAsString(date);
           return obj;
       }
   
       @RequestMapping("/json4")
       public String json4() throws JsonProcessingException {
           ObjectMapper mapper = new ObjectMapper();
           Date oridate = new Date();
           //不使用时间戳的方式
           mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
           //自定义时间格式
           SimpleDateFormat format = new SimpleDateFormat("yy-MM-dd HH:mm:ss");
           mapper.setDateFormat(format);
           String obj = mapper.writeValueAsString(oridate);
           return obj;
       }
   
       @RequestMapping("/json5")
       public String json5() throws JsonProcessingException {
           Date oridate = new Date();
           //使用自建工具类
           String obj = JsonUtils.getJson(oridate);
           return obj;
       }
   
   
       @RequestMapping("/json6")
       //队列
       public String json6() throws JsonProcessingException {
           List<User> userList = new ArrayList<User>();
           User user1 = new User("大头儿子", 6, "男");
           User user2 = new User("也是大头儿子", 6, "男");
           User user3 = new User("还是大头儿子", 6, "男");
           User user4 = new User("不是大头儿子", 6, "女");
           userList.add(user1);
           userList.add(user2);
           userList.add(user3);
           userList.add(user4);
           //使用自建工具类
           String users = JsonUtils.getJson(userList);
           return users;
       }
   

4. 自建工具类

   public class JsonUtils {
       public static String getJson(Object object) {
           return getJson(object, "yy-MM-dd HH:mm:ss");
       }
       public static String getJson(Object object, String dateformat) {
           ObjectMapper mapper = new ObjectMapper();
           mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
           SimpleDateFormat format = new SimpleDateFormat(dateformat);
           mapper.setDateFormat(format);
           try {
               return mapper.writeValueAsString(object);
           } catch (JsonProcessingException e) {
               e.printStackTrace();
           }
           return null;
       }
   }
   

fastjson

1. 导包

   <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
   <dependency>
       <groupId>com.alibaba</groupId>
       <artifactId>fastjson</artifactId>
       <version>1.2.62</version>
   </dependency>
   

2. json解析

   @RequestMapping("/json7")
   //队列
   public String json7() throws JsonProcessingException {
       List<User> userList = new ArrayList<User>();
       User user1 = new User("大头儿子", 6, "男");
       User user2 = new User("也是大头儿子", 6, "男");
       User user3 = new User("还是大头儿子", 6, "男");
       User user4 = new User("不是大头儿子", 6, "女");
       userList.add(user1);
       userList.add(user2);
       userList.add(user3);
       userList.add(user4);
       String users = JSON.toJSONString(userList);
       return users;
   }
   

3. 更多

   System.out.println("*******Java对象 转 JSON字符串*******");
   String str1 = JSON.toJSONString(users);
   System.out.println("JSON.toJSONString(list)==>"+str1);
   String str2 = JSON.toJSONString(user1);
   System.out.println("JSON.toJSONString(user1)==>"+str2);
   
   System.out.println("
   ****** JSON字符串 转 Java对象*******");
   User jp_user1=JSON.parseObject(str2,User.class);
   System.out.println("JSON.parseObject(str2,User.class)==>"+jp_user1);
   
   System.out.println("
   ****** Java对象 转 JSON对象 ******");
   JSONObject jsonObject1 = (JSONObject) JSON.toJSON(user2);
   System.out.println("(JSONObject) JSON.toJSON(user2)==>"+jsonObject1.getString("name"));
   
   System.out.println("
   ****** JSON对象 转 Java对象 ******");
   User to_java_user = JSON.toJavaObject(jsonObject1, User.class);
   System.out.println("JSON.toJavaObject(jsonObject1, User.class)==>"+to_java_user);