Question

围绕Lambda Expressions的一个简单问题。我有以下文字：

{＆＃34;主机＆＃34;：[{＆＃34;磁盘＆＃34;：[{＆＃34;路径＆＃34;：＆＃34; /＆＃34;＆＃34; SPACE_USED＆＃34;：0.608}]，＆＃34;主机名＆＃34;：＆＃34;主机1＆＃34;}，{＆＃34;磁盘＆＃34;：[{＆＃34;路径＆＃34;：＆＃ 34; /＆＃34;＆＃34; SPACE_USED＆＃34;：0.79}，{＆＃34;路径＆＃34;：＆＃34; /选择＆＃34;＆＃34; SPACE_USED＆＃34;：0.999 }]，＆＃34;主机名＆＃34;：＆＃34;主机2＆＃34;}，{＆＃34;磁盘＆＃34;：[{＆＃34;路径＆＃34;：＆＃34; /＆＃ 34;，＆＃34; SPACE_USED＆＃34;：0.107}]，＆＃34;主机名＆＃34;：＆＃34; host3上＆＃34;}]}

我想将上述内容格式化为每行阅读：

{＆＃34;主机名＆＃34;：＆＃34;主机1＆＃34;，＆＃34;磁盘＆＃34;：[＆＃34;路径＆＃39; /＆＃39;已经使用了60.8％＆＃34;]}

{＆＃34;主机名＆＃34;：＆＃34;主机2＆＃34;，＆＃34;磁盘＆＃34;：[＆＃34;路径＆＃39; /＆＃39;已经使用了79％＆＃34;，＆＃34; Path＆＃39; / opt＆＃39;使用了99.9％＆＃34;]}

{＆＃34;主机名＆＃34;：＆＃34;主机3＆＃34;，＆＃34;磁盘＆＃34;：[＆＃34;路径＆＃39; /＆＃39;已经使用了10.7％＆＃34;]}

我在.stream（）。map（）和.collect（）周围尝试了一些排列，但不知怎的，我得到了我需要的输出。如果问题相当愚蠢，那么任何帮助都会受到高度赞赏和道歉。感谢。

Answer 1

您可以使用Jackson 2 Library将JSON-String转换为Java对象。

在你的具体案例中你可以例如创建以下类：

<强> Disk.java

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({"path", "space_used"})
public class Disk implements Serializable {

  private final static long serialVersionUID = -6127352847480270783L;

  @JsonProperty("path")
  private String path;

  @JsonProperty("space_used")
  private Double spaceUsed;

  @JsonIgnore
  private Map<String, Object> additionalProperties = new HashMap<String, Object>();

  @JsonProperty("path")
  public String getPath() {
    return path;
  }

  @JsonProperty("path")
  public void setPath(String path) {
    this.path = path;
  }

  @JsonProperty("space_used")
  public Double getSpaceUsed() {
    return spaceUsed;
  }

  @JsonProperty("space_used")
  public void setSpaceUsed(Double spaceUsed) {
    this.spaceUsed = spaceUsed;
  }

  @JsonAnyGetter
  public Map<String, Object> getAdditionalProperties() {
    return this.additionalProperties;
  }

  @JsonAnySetter
  public void setAdditionalProperty(String name, Object value) {
    this.additionalProperties.put(name, value);
  }
}

Host.java

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({"disks", "hostname"})
public class Host implements Serializable {

  private final static long serialVersionUID = -1972892789688333505L;

  @JsonProperty("disks")
  private List<Disk> disks = null;

  @JsonProperty("hostname")
  private String hostname;

  @JsonIgnore
  private Map<String, Object> additionalProperties = new HashMap<String, Object>();

  @JsonProperty("disks")
  public List<Disk> getDisks() {
    return disks;
  }

  @JsonProperty("disks")
  public void setDisks(List<Disk> disks) {
    this.disks = disks;
  }

  @JsonProperty("hostname")
  public String getHostname() {
    return hostname;
  }

  @JsonProperty("hostname")
  public void setHostname(String hostname) {
    this.hostname = hostname;
  }

  @JsonAnyGetter
  public Map<String, Object> getAdditionalProperties() {
    return this.additionalProperties;
  }

  @JsonAnySetter
  public void setAdditionalProperty(String name, Object value) {
    this.additionalProperties.put(name, value);
  }
}

HostContainer.java

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({"hosts"})
public class HostContainer implements Serializable {

  private final static long serialVersionUID = 7917934809738573749L;

  @JsonProperty("hosts")
  private List<Host> hosts = null;

  @JsonIgnore
  private Map<String, Object> additionalProperties = new HashMap<String, Object>();

  @JsonProperty("hosts")
  public List<Host> getHosts() {
    return hosts;
  }

  @JsonProperty("hosts")
  public void setHosts(List<Host> hosts) {
    this.hosts = hosts;
  }

  @JsonAnyGetter
  public Map<String, Object> getAdditionalProperties() {
    return this.additionalProperties;
  }

  @JsonAnySetter
  public void setAdditionalProperty(String name, Object value) {
    this.additionalProperties.put(name, value);
  }

}

用法：

  public void parseMessage() throws IOException {
    String msg = "{\"hosts\":[{\"disks\":[{\"path\":\"/\",\"space_used\":0.608}]," +
                 "\"hostname\":\"host1\"},{\"disks\":[{\"path\":\"/\",\"space_used\":0.79}," +
                 "{\"path\":\"/opt\",\"space_used\":0.999}],\"hostname\":\"host2\"}," +
                 "{\"disks\":[{\"path\":\"/\",\"space_used\":0.107}],\"hostname\":\"host3\"}]}";
    ObjectMapper mapper = new ObjectMapper();

    // This object will contain all the information you need, access it using e.g. getHosts();
    HostContainer hostContainer = mapper.readValue(msg, HostContainer.class);
  }

Java Lambda Expression消息格式化，中断和字符串连接

1 个答案: