accesstest.java

《Java核心技术应用开发》电子工业出版社书籍源代码

/**
 *演示数据封装性
 */
package sample;
class EncapTest {
  int a; // default access
  public int b; // public access
  private int c; // private access
  // methods to access c
  void setc(int i) { // set c's value
    c = i;
  }
  int getc() { // get c's value
    return c;
  }
}

public class AccessTest {
  public static void main(String args[]) {
    EncapTest ob = new EncapTest();
    // These are OK，a and b may be accessed directly
    ob.a = 10;
    ob.b = 20;
    // This is not OK and will cause an error
    // ob.c = 30; // Error!
    // You must access c through its methods
    ob.setc(30); // OK
    System.out.println("a，b，and c: " + ob.a + " " +ob.b + " " + ob.getc());
  }
}