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NoSuchFieldException on getClass (). GetField ()

java.lang.NoSuchFieldException: id

The next line throws an exception.

String fieldValue =String.valueOf(studyplanCategory.getClass().getField(filterProperty).get(studyplanCategory));

studyplanCategory is a valid object and has actual values. Due to this exception, the load method and search function in the LazyLoading DataTable of my JSF web application do not work.

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4 answers

An application throws this exception because it does not see the attributes you want to return. The getField () method returns non-private attributes, so if your attributes are private, the method does not see them. You can check out http://docs.oracle.com/javase/tutorial/reflect/member/fieldTrouble.html

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public List<Car> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String,String> filters) {  
        List<Car> data = new ArrayList<Car>();  

        //filter  
        for(Car car : datasource) {  
            boolean match = true;  

            for(Iterator<String> it = filters.keySet().iterator(); it.hasNext();) {  
                try {  
                    String filterProperty = it.next();  
                    String filterValue = filters.get(filterProperty);  
                    String fieldValue = String.valueOf(car.getClass().getField(filterProperty).get(car));  

...

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//EDIT: Man , getDeclaredField(), , , IlegalAccessException. , . , .

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Javadoc Class.getField(...):

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studyplanCategory.getClass().getField(filterProperty)

, NoSuchFieldException. :

studyplanCategory.getClass().getDeclaredField(filterProperty)

:

Field field = studyplanCategory.getClass().getDeclaredField(filterProperty);
field.setAccessible(true);
field.get(studyplanCategory);
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getClass().getField():

getDeclaredField() getField()

1)

String propertyName = "test";<br/>
Class.forName(this.getClass().getName()).getDeclaredField(propertyName);

2)

String propertyName = "name";<br/>
Replace **"HelloWorld"** with your class name<br/>
HelloWorld.class.getDeclaredField(propertyName)
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  private Object getVariableValue(Object clazz, String variableName) {
    try {
        Field field = clazz.getClass().getField(variableName);
        return field.get(clazz);
    } catch (NoSuchFieldException e) {
        return "";
    } catch (IllegalAccessException e) {
        return "";
    }

}
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