public class Student {
	private  String  name; //姓名
    private String age; //年齡
    private String sex; //性別
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
    
}

// 判斷1  ： 這里會(huì)返回 true
Student student = null;
if(student == null){
  return true;  
}else{
  return false;  
}

// 判斷2 ： 這里會(huì)返回 false
Student student = new Student ();
if(student == null){
  return true;  
}else{
  return false;  
}

com.example.demo.text.Student@15db9742

Exception in thread "main" java.lang.NullPointerException
	at com.example.demo.text.Test.main(Test.java:13)

@RequestMapping(value = "/personInfoMoveIn", method = RequestMethod.POST)
public ResultDto personInfoMoveIn(@RequestBody Map<String, Object> params) {
    String personInfoId = params.get("personInfoId").toString();
	return personInfoService.personInfoMoveIn(params);
}

 params.get("personInfoId") == null ? "" : params.get("districtId").toString();

public static boolean isBlankOrEmpty(Object object) {
   if (null == object) {
        return false;
    }
    if (object.toString().equals("")) {
        return false;
    }
    return true;
}

public static Boolean isObjectNotEmpty(Object obj) {
 	String str = ObjectUtils.toString(obj, "");
  	return StringUtils.isNotBlank(str);
 }