问该类中getter/setter的用途

EN

public class Page {

private int mImageId;
private String mText;

private Choice mChoice1;
private Choice mChoice2;


public Page(int imageId, String text, Choice choice1, Choice choice2 ){
    mImageId = imageId;
    mText = text;
    mChoice1 = choice1;
    mChoice2 = choice2;
} 

 // start of getters/setters
public int getImageId(){

    return mImageId;
}

public void setImageId(int id){
    mImageId = id;
}

public String getText() {
    return mText;
}

public void setText(String text) {
    mText = text;
}

public Choice getChoice1() {
    return mChoice1;
}

public void setChoice1(Choice choice1) {
    mChoice1 = choice1;
}// Choice 1

public Choice getChoice2() {
    return mChoice2;
}

public void setChoice2(Choice choice2) {
    mChoice2 = choice2;
}// Choice 2