java - 创建以字符串形式出现的类的新实例并更新集合方法

Question

我正在获取类名(字符串)，并且该类有很少的集合方法和由于它是动态的(我可以得到任何类)，我需要使用所有的集合方法并用 data 更新它。我该怎么做？

为了获取类字段，我使用以下代码

className = obj.getClassName();
Class<?> classHandle = Class.forName(className);

例如，我需要更新名字和姓氏

public class Person {

private String id;
    private String firstName;
    private String lastName;

    public void setLastName(String lastName) {

        this.lastName = lastName;
    }

    public void setfirstName(String firstName) {

        this.firstName = firstName;
    }

或者不同的类(class)，我需要设置薪水和工作描述

public class Job {


  private double salery;
  private String jobDescr;


  public void setSalery(double salery) {
    this.salery = salery;
  }

  public void setJobDescr(String jobDescr) {
    this.jobDescr = jobDescr;
  }

}

Answer 1

首先，你所做的很好。我假设你有一个 Map<String, Object>要设置的属性:attributeMap .

//this is OK
className = obj.getClassName();
Class<?> classHandle = Class.forName(className);

//got the class, create an instance - no-args constructor needed!
Object myObject = classHandle.newInstance();

//iterate through all the methods declared by the class  
for(Method method : classHandle.getMethods()) {
   //check method name
   if(method.getName().matches("set[A-Z].*") 
       //check if it awaits for exactly one parameter
       && method.getParameterTypes().length==1) {

       String attributeName = getAttributeName(method.getName());
       //getAttributeName would chop the "set", and lowercase the first char of the name of the method (left out for clarity)

       //To be extra nice, type checks could be inserted here...
       method.invoke(myObject, attributeMap.get(attributeName));            

   }
}

当然，还有很多异常处理要做，这只是要做的事情的基本想法...

推荐阅读:

• Class
• Class.getMethods()
• Method
• Method.invoke()