Java中常用解析工具jackson及fastjson的使用

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.3</version>
</dependency>

package com.lxc.SpringBoot.controller;
 
 
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.WEB.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
@RestController // 这个类下边的所有方法，都会返回json，不会返回一个视图！
public class Json {
 
    @RequestMapping(value = "/json")
    public String json() throws Exception{
        User user = new User("吕星辰", "888", 20);
        ObjectMapper obj = new ObjectMapper();
        String jsonObject = obj.writeValueAsString(user);
        return jsonObject;
    }
    // 为测试方便，在这里写一个实体类
    public static class User {
        private String userName;
 
        public String getUserName() {
            return userName;
        }
 
        public void setUserName(String userName) {
            this.userName = userName;
        }
 
        public String getPassword() {
            return passWord;
        }
 
        public void setPassword(String password) {
            this.password = password;
        }
 
        public int getAge() {
            return age;
        }
 
        public void setAge(int age) {
            this.age = age;
        }
 
        private String password;
        private int age;
        public User(String userName, String password, int age) {
            this.userName = userName;
            this.password = password;
            this.age = age;
        }
    }
}

package com.lxc.springboot.controller;
 
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
import java.util.ArrayList;
import java.util.List;
 
@RestController
public class Json {
 
    @RequestMapping(value = "/json")
    public String json() throws Exception{
        // 创建一个集合
        List<User> userList = new ArrayList<>();
        for(int i = 0; i < 3; i ++) {
            userList.add(new User("用户名"+i, "密码"+i, 20+i));
        }
        ObjectMapper obj = new ObjectMapper();
        String jsonObject = obj.writeValueAsString(userList);
        return jsonObject;
    }
    // 上边有实体类，这里省略
}

@RestController
public class Json {
 
    @RequestMapping(value = "/json")
    public String json() throws Exception{
        // 创建一个Map
        Map<String, Object> map = new HashMap<>();
        map.put("name", "测试名");
        map.put("age", 20);
        ObjectMapper obj = new ObjectMapper();
        String jsonObject = obj.writeValueAsString(map);
        return jsonObject;
    }
}

@RestController
public class Json {
 
    @RequestMapping(value = "/json")
    public String json() throws Exception{
        Date date = new Date();
        ObjectMapper obj = new ObjectMapper();
        String jsonObject = obj.writeValueAsString(date);
        return jsonObject;
    }
}

@RestController
public class Json {
 
    @RequestMapping(value = "/json")
    public String json() throws Exception{
        Date date = new Date();
        SimpleDateFORMat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        String time = sdf.format(date); // "2021-06-27 05:19:33"
        ObjectMapper obj = new ObjectMapper();
        String jsonObject = obj.writeValueAsString(time);
        return jsonObject;
    }
}

package com.lxc.springboot.utils;
 
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
 
import java.text.SimpleDateFormat;
 
public class JavaUtils {
    
    public static String getJson(Object object, String format) {
        ObjectMapper objectMapper = new ObjectMapper();
        // 不使用时间戳的方式
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        // 自定义时间格式
        SimpleDateFormat sdf = new SimpleDateFormat(format);
        // 设置时间格式化
        objectMapper.setDateFormat(sdf);
        try {
            String jsonValue = objectMapper.writeValueAsString(object);
            return jsonValue;
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }
    public static String getJson(Object object) {
        return getJson(object, "yyyy-MM-dd hh:mm:ss");
    }
}

<!--下边依赖跟aop没关系，只是项目中用到了 JSONObject，所以引入fastjson-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.70</version>
</dependency>

@RestController
public class Json {
 
    @RequestMapping(value = "/json")
    public String json() throws Exception{
        List<User> userList = new ArrayList<>();
        userList.add(new User("1", "1", 20));
        String res = JSON.toJSONString(userList);
        return res;
    }