<一>认识泛型

不用泛型：

1 class diqiujw{ 2     public Object jing; 3     public Object wei; 4     public Object getJing() { 5         return jing; 6     } 7     public void setJing(Object jing) { 8         this.jing = jing; 9     }10     public Object getWei() {11         return wei;12     }13     public void setWei(Object wei) {14         this.wei = wei;15     }16     17 }18 public class Test2 19 {20     public static void main(String[] args){21         diqiujw dq=new diqiujw();22         dq.setJing(111);23         dq.setWei(120);24         int j=(Integer) dq.getJing();25         int w=(Integer) dq.getWei();26         System.out.print("经度："+j+"纬度："+w);27     }28 }

使用泛型：

class diqiu 
     
      {
   //设置一个不确定的值，通常为
      
           public T jing;    public T wei;    public T getJing() {        return jing;    }    public void setJing(T jing) {        this.jing = jing;    }    public T getWei() {        return wei;    }    public void setWei(T wei) {        this.wei = wei;    }}public class Test1{    public static void main(String[] args){        diqiu
       
         dq=new diqiu
        
         ();//设置数据类型，可以是
         
           ||
          
            ||
           
             ... dq.setJing("111"); dq.setWei("332"); System.out.println("经度："+dq.getJing()+"纬度："+dq.getWei()); }}
           
          
         
        
       
      
     

<二>构造方法中使用泛型：

1 class ceshi
     
      { 2     public T value; 3     public ceshi(T value){ 4         this.value=value; 5     } 6     public T getValue() { 7         return value; 8     } 9     public void setValue(T value) {10         this.value = value;11     }    12 }13 public class Generic02 {14     public static void main(String[] args) {15     ceshi
      
        cs=new ceshi
       
        ("鹏鹏");16     System.out.print(cs.getValue());17 18     }20 }
       
      
     

 

 <三>指定多个泛型：

1 class Gen
     
      { 2     public T table; 3     public K key; 4     public T getTable() { 5         return table; 6     } 7     public void setTable(T table) { 8         this.table = table; 9     }10     public K getKey() {11         return key;12     }13     public void setKey(K key) {14         this.key = key;15     }    16 }17 public class Generic03 {18     public static void main(String[] args) {19         Gen
      
        g=new Gen
       
        ();20         g.setTable("hello");21         g.setKey(2015);22         System.out.print(g.getTable()+"  "+g.getKey());23     }24 }
       
      
     

<四>泛型——通配符：

1 class Gen
     
      { 2     public T value; 3  4     public T getValue() { 5         return value; 6     } 7  8     public void setValue(T value) { 9         this.value = value;10     }11     public String toString(){
   //为了能够方便具体得到key的值重写toString方法12         return this.getValue().toString();13     }14 }15 public class Generic03 {16     public static void main(String[] args) {17         Gen
      
        g=new Gen
       
        ();18         g.setValue(100);19         Generic03.tell(g);20     }21     public static void tell(Gen
         n){
   //通配符：
        22         System.out.print(n);23     }24 }
       
      
     

 <五>泛型方法：

1 class Gen{ 2     public 
     
      T say(T s){ 3         return s; 4     } 5 } 6 public class Generic03 { 7     public static void main(String[] args) { 8         Gen g=new Gen(); 9         String str=g.say("可以是字符串");10         System.out.println(str);11         int in=g.say(111);12         System.out.println(in);13     }14 }
     

 <六>泛型数组：

1 class Gen{ 2     public 
     
      void say(T arr[]){ 3     for (int i = 0; i < arr.length; i++) { 4         System.out.print(arr[i]); 5         } 6     System.out.println(); 7     } 8 } 9 public class Generic03 {10     public static void main(String[] args) {11         Gen g=new Gen();12         String arr2[]={"我","在","洛阳"};13         Integer arr[]={2015,11,23};14         g.say(arr);15         g.say(arr2);16     }17 }