Java ActionListener中未初始化的变量

我正在尝试让这个程序打印选择的顶部和外壳，按照现在设置的方式，它只打印名称。我尝试将所有字符串初始化为空字符串“”。但无论单击哪个按钮，字符串始终为空，即使不支持使用if语句来更改它们

这是密码

public void actionPerformed(ActionEvent e) {
    if(e.getSource() == output){    
        String str2, str3, str4, str5;
        String str1 = txtName.getText();
        if(e.getSource() == optThick){
            str2  = "thick crust";
        }
        else if (e.getSource() == optThin){
             str2 = "thin crust ";
        }
        if(e.getSource() == cbCheese){
            str3 = "Cheese ";
        }
        if(e.getSource() == cbOlives){
             str4 = "Olives ";
        }
        if(e.getSource() == cbTomatoes){
             str5 = "Tomatoes ";
        }

        textArea.setText("Name : " + str1 + "\n" + "Crust: " + str2 + "\n" + "Toppings: " + str3 + str4 + str5); 
    }
}
}

---

所有if语句都在外部语句中。是吗？

如果有人想知道，我就是这样让它工作的

public void actionPerformed(ActionEvent e) {
    if(e.getSource() == output){    
        String str2 = "", str3 = "", str4 = "", str5 = "";
        String str1 = txtName.getText();
        if(optThick.isSelected()){
            str2  = "Thick crust";
        }
        else if (optThin.isSelected()){
             str2 = "Thin crust ";
        }
        if(cbCheese.isSelected()){
            str3 = "Cheese ";
        }
        if(cbOlives.isSelected()){
             str4 = "Olives ";
        }
        if(cbTomatoes.isSelected()){
             str5 = "Tomatoes ";
        }

        textArea.setText(String.format("Name: %s \nCrust: %s\n Toppings: %s%s%s ",str1, str2, str3, str4, str5)); 
    }
}

---

“optThick”和这些变量的背后是什么？如果你像“==”那样比较它们，你可能只是比较可能失败的对象。调试器说了什么？变量str2、str3、str4和str5可能尚未初始化

public void actionPerformed(ActionEvent e) {
    if(e.getSource() == output){    
        String str2 = "", str3 = "", str4 = "", str5 = "";
        String str1 = txtName.getText();
        if(optThick.isSelected()){
            str2  = "Thick crust";
        }
        else if (optThin.isSelected()){
             str2 = "Thin crust ";
        }
        if(cbCheese.isSelected()){
            str3 = "Cheese ";
        }
        if(cbOlives.isSelected()){
             str4 = "Olives ";
        }
        if(cbTomatoes.isSelected()){
             str5 = "Tomatoes ";
        }

        textArea.setText(String.format("Name: %s \nCrust: %s\n Toppings: %s%s%s ",str1, str2, str3, str4, str5)); 
    }
}