Automatic conversion of form String input values to other java types dynamically to generate a class instance

Question

I have a form which is accepting only String variables but I want to generate a Class instance such that each string property is converted to its corresponding type identified by property name in the class.

For e.g. If I have three fields in a form with the name of NAME, ANNUAL SALARY and isLocalResident. I want to convert this form to an instance of Class1 where these properties are of String, BigInteger and Boolean type.

How do I do that?

Currently I am using BeanUtil Property of java, but it doesn't fulfill my requirement because it just doesn't covert to its required types; rather it asks me a setter and getter of the desired type. Please help me out of this. Any suggestion would be appreciated?

P note that this form is dynamic, i.e. number and name of fields shall depend on another input. The following code represents generating instance emp1 for Employee1 class.

public Empolyee1 setContent(List<String> nameList, List<String> valueList) {
    Empolyee1 emp1 = new Empolyee1();

    for(String attr : nameList) {
        if(attr.equalsIgnoreCase("name")) { 
            if(valueList.get(nameList.indexOf("name")) != null && !valueList.get(nameList.indexOf("name")).trim().equals("")) {
                emp1.setName(valueList.get(nameList.indexOf("name")));
            }
    } else {
        if(attr.equalsIgnoreCase("ANNUAL SALARY")) {
            if(valueList.get(nameList.indexOf("ANNUAL SALARY")) != null && !valueList.get(nameList.indexOf("ANNUAL SALARY")).trim().equals("")) {
                  emp1.setAnnualSalary(valueList.get(nameList.indexOf("ANNUAL SALARY")));
            }
        } else {
            if(attr.equalsIgnoreCase("isLocalResident")) {
                if(valueList.get(nameList.indexOf("isLocalResident")) != null && !valueList.get(nameList.indexOf("isLocalResident")).trim().equals("")) {
                    emp1.setIsLocalResident(valueList.get(nameList.indexOf("isLocalResident")));    
                }
            } 
        }
    }
    return empl1;
}

It's not clear: you want to instance a class with a dynamic number of attributes (of a dynamic type) automatically converted ? You don't know the number and type of the attributes, but do you know the overall number and type of attributes ? Do you know the (for example) 50 possible attributes, that in the form could combine in every permutation ? — Andrea Ligios, Sep 21 '16 at 08:19
Refer this. http://stackoverflow.com/questions/13868986/dynamically-create-an-object-in-java-from-a-class-name-and-set-class-fields-by-u — Vel, Sep 22 '16 at 02:07
@AndreaLigios , Yes I know the overall number and type of attributes. For example, I have 10 different classes with total number of 100 attributes. And each class may have different number of attributes. And i have xsd for each of the 10 classes containing getter and setter. Now, i have to set a class selected from UI. — jaswant meena, Sep 23 '16 at 04:48
Note that using a for each loop and `indexOf` isn't a good way of doing this: use a regular for loop with an int index (e.g. `i`), and use this to get corresponding elements of `nameList` and `valueList` (e.g. `String attr = nameList.get(i); String value = valueList.get(i).trim();`). Of course, using a `Map` would be better again... — Andy Turner, Nov 18 '16 at 20:26

score 0 · Answer 1 · answered Jan 14 '17 at 08:22

The key point is converting field name to Java Bean property name. toPropertyName method is a simple implementation based on the example of your question. (Bewared! if you need to support nested bean property, make sure your code prevent the potential class loader vulnerability of CVE-2014-0114...)

public static String toPropertyName(String s) {
    int len = s.length();
    StringBuilder sb = new StringBuilder(len);
    boolean toUpper = false;
    boolean isLower = false;
    for (int i = 0; i < len; i++) {
        char ch = s.charAt(i);
        if (Character.isLetterOrDigit(ch)) {
            if (Character.isUpperCase(ch)) {
                sb.append((toUpper || isLower)?ch:Character.toLowerCase(ch));
                isLower = false;
            } else {
                isLower = true;
                sb.append(toUpper?Character.toUpperCase(ch):ch);
            }
            toUpper = false;
        } else {
            isLower = false;
            toUpper = true;
        }
    }
    return sb.toString();
}

public Empolyee1 setContent(List<String> nameList, List<String> valueList) throws Exception {
    HashMap<String, String> map = new HashMap<String, String>();
    Iterator<String> nameIter = nameList.iterator();
    Iterator<String> valueIter = valueList.iterator();
    while (nameIter.hasNext()) {
        String name = (String) nameIter.next();
        map.put(toPropertyName(name), valueIter.hasNext()?valueIter.next():null);
    }
    Empolyee1 emp1= new Empolyee1();
    BeanUtils.populate(emp1, map);
    return emp1;
}

BeanUtils.populate(emp1, map) API is used to take other job. It convert inputed values and call setter of each Java Bean property.

Automatic conversion of form String input values to other java types dynamically to generate a class instance

1 Answers1