springboot常用的json串和返回状态json

一 常用返回状态串

1.1 JsonData工具类

package com.ljf.spt.war.deployment.demo.model;

import java.io.Serializable;

/**
 * @ClassName: JsonData
 * @Description: TODO
 * @Author: liujianfu
 * @Date: 2020/09/08 09:04:49 
 * @Version: V1.0
 **/
public class JsonData implements Serializable {
    /**
     *
     */
    private static final long serialVersionUID = 1L;

    private Integer code; // 状态码 0 表示成功，1表示处理中，-1表示失败
    private Object data; // 数据
    private String msg;// 描述

    public JsonData() {
    }

    public JsonData(Integer code, Object data, String msg) {
        this.code = code;
        this.data = data;
        this.msg = msg;
    }

    // 成功，传入数据
    public static JsonData buildSuccess(String name,String msg) {
        return new JsonData(0, name, msg);
    }

    // 成功，传入数据
    public static JsonData buildSuccess(Object data) {
        return new JsonData(0, data, null);
    }

    // 失败，传入描述信息
    public static JsonData buildError(String msg) {
        return new JsonData(-1, null, msg);
    }

    // 失败，传入描述信息,状态码
    public static JsonData buildError(String msg, Integer code) {
        return new JsonData(code, null, msg);
    }

    // 成功，传入数据,及描述信息
    public static JsonData buildSuccess(Object data, String msg) {
        return new JsonData(0, data, msg);
    }

    // 成功，传入数据,及状态码
    public static JsonData buildSuccess(Object data, int code) {
        return new JsonData(code, data, null);
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    @Override
    public String toString() {
        return "JsonData [code=" + code + ", data=" + data + ", msg=" + msg
                + "]";
    }
}

二 json串的转换

2.1 引入pom文件

  <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.13</version>
        </dependency>

2.2 json转换工具

package com.ljf.spt.war.deployment.demo.utils;


import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.annotate.JsonSerialize;
import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;
import org.codehaus.jackson.type.JavaType;
import org.codehaus.jackson.type.TypeReference;
import org.springframework.util.StringUtils;

import java.io.IOException;
import java.text.SimpleDateFormat;

/**
 * @ClassName: JsonUtils
 * @Description: TODO
 * @Author: liujianfu
 * @Date: 2020/09/08 08:33:25 
 * @Version: V1.0
 **/
public class JsonUtils {

    private static ObjectMapper objectMapper = new ObjectMapper();

    static {
        // 对象字段全部列入
        objectMapper.setSerializationInclusion(JsonSerialize.Inclusion.NON_DEFAULT);

        // 取消默认转换timestamps形式
        objectMapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS,false);

        // 忽略空bean转json的错误
        objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS,false);

        // 统一日期格式yyyy-MM-dd HH:mm:ss
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

        // 忽略在json字符串中存在,但是在java对象中不存在对应属性的情况
        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false);
    }

    /**
     * Object转json字符串
     * @param obj
     * @param <T>
     * @return
     */
    public static <T> String obj2String(T obj){
        if (obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String) obj : objectMapper.writeValueAsString(obj);
        } catch (Exception e) {
            System.out.println("Parse object to String error");
            e.printStackTrace();
            return null;
        }
    }

    /**
     * Object转json字符串并格式化美化
     * @param obj
     * @param <T>
     * @return
     */
    public static <T> String obj2StringPretty(T obj){
        if (obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String) obj : objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
        } catch (Exception e) {
            System.out.println("Parse object to String error");
            e.printStackTrace();
            return null;
        }
    }

    /**
     * string转object
     * @param str json字符串
     * @param clazz 被转对象class
     * @param <T>
     * @return
     */
    public static <T> T string2Obj(String str,Class<T> clazz){
        if (StringUtils.isEmpty(str) || clazz == null){
            return null;
        }
        try {
            return clazz.equals(String.class)? (T) str :objectMapper.readValue(str,clazz);
        } catch (IOException e) {
            System.out.println("Parse String to Object error");
            e.printStackTrace();
            return null;
        }
    }

    /**
     * string转object
     * @param str json字符串
     * @param typeReference 被转对象引用类型
     * @param <T>
     * @return
     */
    public static <T> T string2Obj(String str, TypeReference<T> typeReference){
        if (StringUtils.isEmpty(str) || typeReference == null){
            return null;
        }
        try {
            return (T)(typeReference.getType().equals(String.class)? str :objectMapper.readValue(str,typeReference));
        } catch (IOException e) {
            System.out.println("Parse String to Object error");
            e.printStackTrace();
            return null;
        }
    }

    /**
     * string转object 用于转为集合对象
     * @param str json字符串
     * @param collectionClass 被转集合class
     * @param elementClasses 被转集合中对象类型class
     * @param <T>
     * @return
     */
    public static <T> T string2Obj(String str,Class<?> collectionClass,Class<?>... elementClasses){
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass,elementClasses);
        try {
            return objectMapper.readValue(str,javaType);
        } catch (IOException e) {
            System.out.println("Parse String to Object error");
            e.printStackTrace();
            return null;
        }
    }

}

2.3 testJson转换

package com.ljf.spt.war.deployment.demo.utils;

import com.ljf.spt.war.deployment.demo.model.User;
import org.codehaus.jackson.type.TypeReference;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @ClassName: TestJson
 * @Description: TODO
 * @Author: liujianfu
 * @Date: 2021/03/28 18:46:34 
 * @Version: V1.0
 **/
public class TestJson {
    public static void main(String args[]){
      System.out.println("");
      User u=new User();
      u.setAge(23);
      u.setPhone("188129042324");
      u.setPwd("234");
      u.setCreateTime(new Date());
      List<User> uList=new ArrayList<User>();
      uList.add(u);
      uList.add(u);
      //json转user
       String s= JsonUtils.obj2String(u);
     //  s="{\"code\":\"200\",\"body\":"+s+"}";
       System.out.println("s:"+s);
       //user转json
        User user= JsonUtils.string2Obj(s,User.class);
        System.out.println("userList:"+user.toString());
        //
        String userListStr =JsonUtils.obj2StringPretty(uList);
        List<User> userListObj =JsonUtils.string2Obj(userListStr, new TypeReference<List<User>>() {});
        for(User u2:userListObj){
            System.out.println("u2:"+u2.getAge());
        }

    }
}