Question

说我的课程AccountPojo和GetAccountPojo的setter和getter方法如下所示。

public class AccountPojo {

    private String dataList;
    private String dataSet;

    public String getDataList() {
        return dataList;
    }

    public void setDataList(String dataList) {
        this.dataList = dataList;
    }

    public String getDataSet() {
        return dataSet;
    }

    public void setDataSet(String dataSet) {
        this.dataSet = dataSet;
    }
} 

public class GetAccountsPojo {

    private String accountId;
    private int noOfAccounts;

    public String getAccountId() {
        return accountId;
    }

    public void setAccountId(String accountId) {
        this.accountId = accountId;
    }

    public int getNoOfAccounts() {
        return noOfAccounts;
    }

    public void setNoOfAccounts(int noOfAccounts) {
        this.noOfAccounts = noOfAccounts;
    }
}

现在我有Test课程，如下所示

public Class Test {

    public static void main(String[] args) {

        Class cls = Class.forName("com.org.temp."+ClassName); // ClassName(AccountPojo/GetAccountPojo) here I know already which class is getting called.

        Object clsInstance = (Object) cls.newInstance();

        System.out.println("The cls is==" + cls+" and classInstance is=="+clsInstance);

    // Here I want to access getter and setter methods of AccountPojo and GetAcoountPojo dynamically, no hard coding

    }   
}

Answer 1

不要使用原始类。如果您知道已经调用了哪个类，请使用类型化类。

    try {
        AccountPojo obj = AccountPojo.class.newInstance();
        Method setDataList = AccountPojo.class.getMethod("setDataList");
        setDataList.setAccessible(true); // This is important if you want to access protected or private method. For public method you can skip
        setDataList.invoke(obj, "123");
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    }

Answer 2

您是否尝试过获取调用类的所有方法并仅按名称过滤掉getter方法并调用它们？

 Method[] methods =  cls.getDeclaredMethods();

             for (Method m: methods) {
                 if(m.getName().startsWith("get")) {
                     m.invoke(clsInstance);
                 }
             }

这解决了我们的一半问题，因为在没有任何参数的情况下调用getter。但是如果需要调用setter方法，则需要指定参数。例如，要调用接受字符串参数方法的setter，如下所示：

m.invoke(clsInstance, "some string argument");

可以使一个解决方案接受一个对象类型值并对它们进行类型转换，同时将它分配给实际的类变量。

现在你的pojo类看起来如下：

public class AccountPojo {

private String dataList;
private String dataSet;

public String getDataList() {
    return dataList;
}

public void setDataList(Object dataList) {
    this.dataList = (String) dataList;
}

public String getDataSet() {
    return dataSet;
}

public void setDataSet(Object dataSet) {
    this.dataSet = (String)dataSet;
}
} 

public class GetAccountsPojo {

private String accountId;
private int noOfAccounts;

public String getAccountId() {
    return accountId;
}

public void setAccountId(Object accountId) {
    this.accountId = (String) accountId;
}

public int getNoOfAccounts() {
    return noOfAccounts;
}

public void setNoOfAccounts(Object noOfAccounts) {
    this.noOfAccounts = (int) noOfAccounts;
}
}

将以下代码添加到您的主要方法：

for (Method m: methods) {
  if(m.getName().startsWith("get")) {
    m.invoke(clsInstance);
  }
  if(m.getName().startsWith("set")) {
    m.invoke(clsInstance, "any argument to be passed here");
  }

}

如何使用Reflection类动态调用和设置和获取方法？

2 个答案: