Java 8：使用lambda表达式的HashMap初始化 [英] Java 8: HashMap initialization with lambda expressions

问题描述

我试图声明和一次定义更大的散列图。这是我怎么做的：

  public HashMap< Integer，Callable< String> opcode_only = new HashMap< Integer，Callable< String>>（）{{
 put（x，y）; 
 put（x，y）; 
}};但是，当我尝试在中使用lambda表达式 c     code>，我打eclipse warrning /错误。这是我在HashMap中使用lambda的方法：
  public HashMap< Integer，Callable< String> opcode_only = new HashMap< Integer，Callable< String>>（）{{
 put（0，（） - > {returnnop;}）; 
 put（1，（） - > {returnnothing ....;}）; 
}}; 
  
 Eclipse以逗号开头的整个lambda部分。 
错误消息：
 令牌上的语法错误，，名称预期
 tokens上的语法错误，表示期望而不是
  
有人知道我做错了什么？是否允许在 HashMap 中使用lambda表达式进行初始化？请帮助。
解决方案
这在Netbeans Lamba版本中可以正常下载：http://bertram2.netbeans.org:8080/job/jdk8lambda/lastSuccessfulBuild/artifact/nbbuild/  
  import java.util。*; 
 import java.util.concurrent.Callable; 
 
 public class StackoverFlowQuery {
 
 public static void main（String [] args）throws Exception {
 
 HashMap< Integer，Callable< String> ; opcode_only = 
 new HashMap< Integer，Callable< String>>（）{
 {
 put（0，（） - > {
 returnnop; 
}）; 
 put（1，（） - > {
 returnnothing ....; 
}）; 
} 
}; 
 System.out.println（opcode_only.get（0）.call（））; 
} 
 
} 
  
 
I'm trying to declare and define larger hash map at once. This is how I do it:
public HashMap<Integer, Callable<String>> opcode_only = new HashMap<Integer, Callable<String>>() {{
    put(x, y);
    put(x, y);
}};
But, when I try to use lambda expressions in body of put, I'm hitting on eclipse warrning/error. This is how I use lambda in HashMap:
public HashMap<Integer, Callable<String>> opcode_only = new HashMap<Integer, Callable<String>>() {{
    put(0, () -> { return "nop"; });
    put(1, () -> { return "nothing...."; });
}};
Eclipse underlines whole part of lambda starting with comma before. 
Error messages:
Syntax error on token ",", Name expected    
Syntax error on tokens, Expression expected instead
Does anybody know what am I doing wrong? Is initialization by lambda expression allowed in HashMap? Please help.
解决方案
This works fine in the Netbeans Lamba builds downloaded from: http://bertram2.netbeans.org:8080/job/jdk8lambda/lastSuccessfulBuild/artifact/nbbuild/
import java.util.*;
import java.util.concurrent.Callable;

public class StackoverFlowQuery {

  public static void main(String[] args) throws Exception {

    HashMap<Integer, Callable<String>> opcode_only = 
          new HashMap<Integer, Callable<String>>() {
            {
              put(0, () -> {
                return "nop";
              });
              put(1, () -> {
                return "nothing....";
              });
            }
          };
    System.out.println(opcode_only.get(0).call());
  }

}


                        
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