我的加密是跳过小写字母

Question

例如，如果我提交字符串＆＃34; TEST3＆gt;＆＃34;它将为您提供＃4; $ 4％DO＆＃34;回来，如果你再加密了＃4;＃4 $％DO＆＃34;它会给你＆＃34; TEST3＆gt;＆＃34;背部。但是，如果您输入＆＃34; TEsT＆＃34;它会给你＆＃34;＃4％＆＃34;返回（注意它跳过了＆＃39;字符），如果你用程序重新加密，你会得到＆＃34; TERQ＆＃34;回来因为它错过了＆＃39;。任何人都可以告诉我为什么？

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package cryptomatic2;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextArea;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

/**
 *
 * @author Zach
 */
public class Cryptomatic2 extends Application {

    @Override
    public void start(Stage primaryStage) {
        String key = "wq";
        GridPane root = new GridPane();
        Label inputLabel = new Label("Input");
        TextArea input = new TextArea();
        input.setMinSize(400, 200);
        Button encrypt = new Button("Encrypt");
        encrypt.setMinSize(100, 100);
        Button decrypt = new Button("Decrypt");
        decrypt.setMinSize(100, 100);
        Label outputLabel = new Label("Output");
        TextArea output = new TextArea();
        output.setMinSize(400, 200);

        root.add(inputLabel, 0, 0);
        root.add(input, 0, 1);
        root.add(encrypt, 0, 2);
        root.add(decrypt, 1, 2);
        root.add(outputLabel, 0, 3);
        root.add(output, 0, 4);

        Scene scene = new Scene(root, 800, 800);

        primaryStage.setTitle("Cryptomatic");
        primaryStage.setScene(scene);
        primaryStage.show();

        encrypt.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent t) {
                String source = input.getText();
                String newString = "";
                if(source.length() % 2 != 0){
                    source = source + " ";
                }
                for(int i = 0; i < source.length(); i+=2){
                    char value1 = source.charAt(i);
                    char value2 = source.charAt(i+1);
                    char key1 = key.charAt(0);
                    char key2 = key.charAt(1);                        
                    int newValue1 = value1 ^ key1;
                    int newValue2 = value2 ^ key2;
                    String encrypted1 = Character.toString((char) newValue1);
                    String encrypted2 = Character.toString((char) newValue2);
                    newString = newString + encrypted1 + encrypted2;
                }
                output.setText(newString);
            }
        });  
    }



    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}