java中的Map每次只能put一次，写段增强的put，可以一次put很多次

package generic;

import java.util.HashMap;
import java.util.Map;

public class TestGenericMap<K, V>{

public Builder<K, V> bd;

public Map<K, V> map(){
return bd.map;
}

public static class Builder<K, V>{
Map<K,V> map;

public Builder(){
map = new HashMap<K,V>();
}

public Builder<K, V> put(K k, V v){
map.put(k, v);
return this;
}
}

public static void main(String[] args){
TestGenericMap.Builder<Integer,String> tm = new TestGenericMap.Builder<Integer,String>();
tm.put(1,"a").put(2,"b").put(3,"c");
System.out.println(tm.map);
}
}

package generic;

import java.util.HashMap;
import java.util.Map;

public class TestGenericMap<K, V>{

public Builder<K, V> bd;

public TestGenericMap(Builder<K, V> bd){
this.bd = bd;
}

public V get(K k){
return bd.map.get(k);
}

public Map<K, V> map(){
return bd.map;
}

public static class Builder<K, V>{
Map<K,V> map;

public Builder(){
map = new HashMap<K,V>();
}

public Builder<K, V> put(K k, V v){
map.put(k, v);
return this;
}

public TestGenericMap<K, V> builder(){
return new TestGenericMap<K, V>(this);
}
}

public static void main(String[] args){
TestGenericMap.Builder<Integer,String> tm = new TestGenericMap.Builder<Integer,String>();
tm.put(1,"a").put(2,"b").put(3,"c").builder().map();
System.out.println(tm.builder().get(2));
}
}