import java.util.Date;public class ParamTest
{
public static void tripleValue(double value)
{
value = 3 * value; System.out.println("End of method: value=" + value);
} public static void swap(Employee a, Employee b) { Employee temp = a; a = b; b= temp; System.out.println("End of method: a=" + a.getName()); System.out.println("End of method: b=" + b.getName()); } public static void tripleSalary(Employee e) { e.raiseSalary(200); System.out.println("End of method: salary=" + e.getSalary()); } public static void main(String[] args) { /* * Test 1: Method can't modify numeric parameters */ System.out.println("Testing tripleValue:"); double percent = 10; System.out.println("Before: percent=" + percent); tripleValue(percent); System.out.println("After: percent=" + percent); /* * Test 2: Methods can change the state of object parameters */ System.out.println("\nTesting tripleSalary"); Employee harry = new Employee("Harry", 50000, new Date()); System.out.println("Before: salary=" + harry.getSalary()); tripleSalary(harry); System.out.println("After: salary=" + harry.getSalary()); /* * Test 3: Methods can't attach new objects to object parameters */ System.out.println("\nTesting swap"); Employee a = new Employee("Alice", 70000, new Date()); Employee b = new Employee("Bob", 60000, new Date()); System.out.println("Before: a=" + a.getName()); System.out.println("Before: b=" + b.getName()); swap(a, b); System.out.println("After: a=" + a.getName()); System.out.println("After: b=" + b.getName()); }
}紼嬪簭鎵撳嵃緇撴灉涓猴細(xì)
Testing tripleValue:
Before: percent=10.0
End of method: value=30.0
After: percent=10.0
Testing tripleSalary
Before: salary=50000.0
End of method: salary=150000.0
After: salary=150000.0
Testing swap
Before: a=Alice
Before: b=Bob
End of method: a=Bob
End of method: b=Alice
After: a=Alice
After: b=Bob
鏈鍚庯紝鎬葷粨涓涓嬶紝Java涓弬鏁頒紶閫掑叏閮ㄩ兘鏄間紶閫掞紒鐗㈣榪欏彞璇濓紝鍩烘湰綾誨瀷鏄間紶閫掞紝鏃犺濡備綍淇敼錛岄兘涓嶄細(xì)褰卞搷鍘熸潵鐨勫彉閲忋傚璞′紶閫掍篃鏄間紶閫掞紝浼犻掔殑鏄璞″紩鐢ㄧ殑鍊鹼紙榪欓噷鏈夌偣涓嶅ソ鐞嗚В錛夛紝絀剁珶浠涔堟槸瀵硅薄寮曠敤鐨勫鹼紵濡?Object obj; //obj = new Object;榪欓噷鐨刼bj灝辨槸瀵硅薄寮曠敤錛屽悗闈竴鍙ヨ瘽鎵撲笂浜?jiǎn)娉ㄩ噴锛寴q欓噷铏界劧obj騫舵病鏈夊垵濮嬪寲錛屼絾鏄紝瀹冭繕鏄湁鍊肩殑錛屽綋鎶妎bj浣滀負(fù)鍙傛暟浼犻掔殑鏃跺欙紝浼犻掔殑鏄痮bj鐨勫箋傚憙錛岀獊鐒跺彂鐜拌嚜宸辯殑瑙ｉ噴鑳藉姏鐪熺殑鏄湁澶熸瑺緙虹殑…涓腑鎰忎箟榪樻槸鑷繁鍒嗚В鍚с?br />
]]>