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复杂JSON字符串转Java嵌套对象

琴水玉 人气:5

背景

实际开发中,常常需要将比较复杂的 JSON 字符串转换为对应的 Java 对象。这里记录下解决方案。

如下所示,是入侵事件检测得到的 JSON 串:

[{"rule_id":"反弹shell","format_output":"进程 pname 反向连接到 %dest_ip%:%dest_port%","info":{"process_events":{"pid":21,"pname":"nginx","cmdline":"curl www.cfda.com","ppid":7,"ppname":"bash"},"proc_trees":[{"pid":21,"pname":"nginx","cmdline":"curl www.cfda.com","ppid":7,"ppname":"bash"}],"containers":{"container_id":"fef4636d8403871c2e56e06e51d609554564adbbf8284dd914a0f61130558bdf","container_name":"nginx","image_id":"4eb8f7c43909449dbad801c50d9dccc7dc86631e54f28b1a4b13575729065be8","status":"Running"},"sockets":{"src_ip":"127.0.0.1","src_port":"8080","type":"1","in_out":"0","dest_ip":"localhost","dest_port":"80"}}}]

方法

预备工作

把上述 json 串放在 src/test/resources 下,写一个文件读写程序来解析。 其实放在哪里不重要,重要的是拿到这个 JSON 串便于后续解析。

public static String readFromSource(String filename) {
    try {
      InputStream is = RWTool.class.getResourceAsStream(filename);
      byte[] bytes = new byte[4096];
      int num = 0;
      String json = "";
      while((num=is.read(bytes))>0){
        json=new String(bytes,0,num);
      }
      return json;
    } catch (Exception ex) {
      throw new RuntimeException(ex.getCause());
    }
}

构建对象模型

首先,要根据这个 JSON 字符串解析出对应的数据模型 AgentDetectEventData。主要就是按照 JSON 串中的 key 的层次结构来建立。

@Getter
@Setter
public class AgentDetectEventData {
    @SerializedName("rule_id")
    @JsonProperty("rule_id")
    private String ruleId;
    @SerializedName("format_output")
    @JsonProperty("format_output")
    private String formatOutput;
    @SerializedName("info")
    @JsonProperty("info")
    private AgentDetectEventDetail info;
}
@Getter
@Setter
public class AgentDetectEventDetail {
    @SerializedName("process_events")
    @JsonProperty("process_events")
    private ProcessEvent processEvent;
    @SerializedName("proc_trees")
    @JsonProperty("proc_trees")
    private List<ProcessTree> procTree;
    @SerializedName("containers")
    @JsonProperty("containers")
    private Container container;
    @SerializedName("sockets")
    @JsonProperty("sockets")
    private Socket socket;
}
@Getter
@Setter
public class ProcessEvent {
    @SerializedName("pid")
    @JsonProperty("pid")
    private String pid;
    @SerializedName("pname")
    @JsonProperty("pname")
    private String pname;
    @SerializedName("cmdline")
    @JsonProperty("cmdline")
    private String cmdline;
    @SerializedName("ppid")
    @JsonProperty("ppid")
    private String ppid;
    @SerializedName("ppname")
    @JsonProperty("ppname")
    private String ppname;
}
@Getter
@Setter
public class ProcessTree {
    @SerializedName("pid")
    @JsonProperty("pid")
    private String pid;
    @SerializedName("pname")
    @JsonProperty("pname")
    private String pname;
    @SerializedName("cmdline")
    @JsonProperty("cmdline")
    private String cmdline;
    @SerializedName("ppid")
    @JsonProperty("ppid")
    private String ppid;
    @SerializedName("ppname")
    @JsonProperty("ppname")
    private String ppname;
}
@Getter
@Setter
public class Container {
    @SerializedName("container_id")
    @JsonProperty("container_id")
    private String containerId;
    @SerializedName("container_name")
    @JsonProperty("container_name")
    private String containerName;
    @SerializedName("image_id")
    @JsonProperty("image_id")
    private String imageId;
    @SerializedName("status")
    @JsonProperty("status")
    private String status;
}
@Getter
@Setter
public class Socket {
    @SerializedName("src_ip")
    @JsonProperty("src_ip")
    private String srcIp;
    @SerializedName("src_port")
    @JsonProperty("src_port")
    private String srcPort;
    @SerializedName("type")
    @JsonProperty("type")
    private String type;
    @SerializedName("in_out")
    @JsonProperty("in_out")
    private String inOut;
    @SerializedName("dest_ip")
    @JsonProperty("dest_ip")
    private String destIp;
    @SerializedName("dest_port")
    @JsonProperty("dest_port")
    private String destPort;
}

这里有两个注意点:

对象模型建立后,就成功了一大半。接下来,就是使用 json 库来解析了。

使用jackson 库解析

public class JsonUtil {
  private static Logger logger = LoggerFactory.getLogger(JsonUtil.class);
  private static final ObjectMapper MAPPER = new ObjectMapper();
  static {
    // 为保持对象版本兼容性,忽略未知的属性
    MAPPER.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    // 序列化的时候,跳过null值
    MAPPER.getSerializationConfig().setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
    // date类型转化
    SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    MAPPER.setDateFormat(fmt);
  }
  /**
   * 将一个json字符串解码为java对象
   *
   * 注意:如果传入的字符串为null,那么返回的对象也为null
   *
   * @param json json字符串
   * @param cls  对象类型
   * @return 解析后的java对象
   * @throws RuntimeException 若解析json过程中发生了异常
   */
  public static <T> T toObject(String json, Class<T> cls) {
    if (json == null) {
      return null;
    }
    try {
      return MAPPER.readValue(json, cls);
    } catch (Exception e) {
      throw new RuntimeException(e.getCause());
    }
  }
  public static <T> String objectToJson(T obj){
    if(obj == null){
      return null;
    }
    try {
      return obj instanceof String ? (String) obj : MAPPER.writeValueAsString(obj);
    } catch (Exception e) {
      return null;
    }
  }
  public static <T> T jsonToObject(String src, TypeReference<T> typeReference){
    if(StringUtils.isEmpty(src) || typeReference == null){
      return null;
    }
    try {
      return (T)(typeReference.getType().equals(String.class) ? src : MAPPER.readValue(src, typeReference));
    } catch (Exception e) {
      logger.warn("Parse Json to Object error",e);
      throw new RuntimeException(e.getCause());
    }
  }
  public static <T> T jsonToObject(String src, Class<?> collectionClass,Class<?>... elementClasses){
    JavaType javaType = MAPPER.getTypeFactory().constructParametricType(collectionClass,elementClasses);
    try {
      return MAPPER.readValue(src, javaType);
    } catch (Exception e) {
      logger.warn("Parse Json to Object error",e);
      throw new RuntimeException(e.getCause());
    }
  }
}

单测:

public class JsonUtilTest {
    @Test
    public void testParseJson() {
        String json = RWTool.readFromSource("/json.txt");
        List<AgentDetectEventData> ade = JsonUtil.jsonToObject(json, new TypeReference<List<AgentDetectEventData>>() {});
        Assert.assertNotNull(ade);
    }
    @Test
    public void testParseJson2() {
        String json = RWTool.readFromSource("/json.txt");
        List<AgentDetectEventData> ade = JsonUtil.jsonToObject(json, List.class, AgentDetectEventData.class);
        Assert.assertNotNull(ade);
    }
}

引入POM依赖为:

<dependency>
       <groupId>org.codehaus.jackson</groupId>
       <artifactId>jackson-mapper-asl</artifactId>
       <version>1.9.4</version>
</dependency>

使用GSON解析

public class GsonUtil {
  static GsonBuilder gsonBuilder = null;
  static {
    gsonBuilder = new GsonBuilder();
    gsonBuilder.setDateFormat("yyyy-MM-dd HH:mm:ss");
  }
  public static Gson getGson() {
    return gsonBuilder.create();
  }
  public static <T> T fromJson(String json, Class<T> cls) {
    return getGson().fromJson(json, cls);
  }
  public static <T> T fromJson(String json, Type type) {
    return getGson().fromJson(json, type);
  }
}

单测:

public class GsonUtilTest {
    @Test
    public void testParseJson() {
        String json = RWTool.readFromSource("/json.txt");
        List<AgentDetectEventData> ade = GsonUtil.fromJson(json, new TypeToken<List<AgentDetectEventData>>(){}.getType());
        Assert.assertNotNull(ade);
    }
}

引入 POM 为:

<dependency>
       <groupId>com.google.code.gson</groupId>
       <artifactId>gson</artifactId>
       <version>2.3.1</version>
</dependency>

不含列表的嵌套对象

如果是不含列表的嵌套对象,则使用带 Class cls 入参的方法:

@Test
public void testParseSimpleNestedJson() {
    String json = "{\"goods\":{\"desc\":\"2箱*250g\",\"goodsId\":8866,\"orderNo\":\"E20210522120237009258\",\"shopId\":659494,\"title\":\"认养一头牛\"},\"order\":{\"bookTime\":1621656157,\"codPay\":false,\"deliveryType\":\"express\",\"orderNo\":\"E20210522120237009258\",\"shopId\":659494,\"userId\":1476}}";
    BookInfo bookInfo = JsonUtil.toObject(json, BookInfo.class);
    Assert.assertNotNull(bookInfo);
}
@Test
public void testParseSimpleNestedJson() {
    String json = "{\"goods\":{\"desc\":\"2箱*250g\",\"goodsId\":8866,\"orderNo\":\"E20210522120237009258\",\"shopId\":659494,\"title\":\"认养一头牛\"},\"order\":{\"bookTime\":1621656157,\"codPay\":false,\"deliveryType\":\"express\",\"orderNo\":\"E20210522120237009258\",\"shopId\":659494,\"userId\":1476}}";
    BookInfo bookInfo = GsonUtil.fromJson(json, BookInfo.class);
    Assert.assertNotNull(bookInfo);
}

读者可以自行解析出 BookInfo 的对象模型。

以上为个人经验,希望能给大家一个参考,也希望大家多多支持。

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