java 对类型的基本操作小结

1.json 字符串转换成对象

SyncCarriageStatusDTO dto= JSON.parseObject(value,SyncCarriageStatusDTO.class);

List<MQPackageParams> pparams = JSON.parseObject(dto.getData(),new TypeReference<List<MQPackageParams>>() {});

2.对象转换成字符串对象

String data = JSON.toJSONString(pkg);

2.枚举字符串转换成枚举类型

RefTypeEnum refType=RefTypeEnum.valueof(dto.getRefType())

3.对象不为空判断

CollectionUtils.isNotEmpty(carriageRefs)

4.XML字符串转换对象或进行XML操作

4.1 利用 JAXBContext

JAXBContext jaxbContext = JAXBContext.newInstance(cls);
       Unmarshaller um = jaxbContext.createUnmarshaller();
       t = (T)um.unmarshal(new StringReader(xmlStr));

4.2 利用 XStream

if(! xmap.containsKey(cls.getName())){

XStream xstream = new XStream(new DomDriver());
   xstream.processAnnotations(cls);
   xstream.ignoreUnknownElements();
   xmap.put(cls.getName(), xstream);
    }

    T t = (T) xmap.get(cls.getName()).fromXML(xmlStr);

  4.3利用 DocumentHelper.parseText(xml)

Node eventType = document.selectSingleNode("//logisticsEvent/eventHeader/eventType");
if (eventType != null && StringUtils.isNotBlank(eventType.getText())) {
type = CainiaoMessageEventTypeEnum.valueOf(eventType.getText().trim());
}

5. 枚举转换：

int packageType = PackageTypeEnum.SMALL.getIndex();

public enum PackageTypeEnum {
/**大包裹*/
BIG(1, "大包裹"),
/**小包裹*/
SMALL(2, "小包裹");

@Getter
@Setter
private int index;
@Getter
@Setter
private String name;

private PackageTypeEnum(int index,String name) {
this.index = index;
this.name = name;
}

public static String getName(int index) {
for (PackageTypeEnum s : PackageTypeEnum.values()) {
if (s.getIndex() == index) {
return s.name;
}
}
return null;
}
}

6.类型转换：

pkg.setWeight(BigDecimal.valueOf(jobPackageDTO.getWeight()));

7.字符串判断是否为空

StringUtils.isBlank(rCode)

8.数组转换成ArrayList

String[] mailNos=mailNo.replaceAll(" ", "").split(",");
List<String> mailnoList=Arrays.asList(mailNos);

9.判断对象类型：

 other instanceof DataExample;

10.数组转换成List类型

String[] arrayA = new String[] { "1", "2", "3", "3", "4", "5" };      
   String[] arrayB = new String[] { "3", "4", "4", "5", "6", "7" };              
   List<String> a = Arrays.asList(arrayA);      
   List<String> b = Arrays.asList(arrayB);