package com.case;import java.util.List;import com.google.common.base.Function;import com.google.common.collect.Lists;/** * Step on the pit with guava *  * @author James * @version $Id: GuavaListsTransFormCase.java, v 0.1 2017年3月24日 下午8:36:36 James Exp $ */public class GuavaListsTransFormCase {    public static void main(String[] args) {        List as = Lists.newArrayList();        A a = new A();        a.setC(1);        as.add(a);        try {            System.out.println("case1 start");            transFormCase1(as);        } catch (Exception e) {            System.out.println(e.getMessage());        } finally {            System.out.println("case1 end");        }        try {            System.out.println("case2 start");            transFormCase2(as);        } catch (Exception e) {            System.out.println(e.getMessage());        } finally {            System.out.println("case2 end");        }    }    private static List transFormCase1(List as) {        return Lists.transform(as, new Function
      
       () {            @Override            public B apply(A input) {                B b = new B();                b.setC(input.getC() / 0);                //...variables                return b;            }        });    }    private static List
        transFormCase2(List
       as) {        return Lists.newArrayList(Lists.transform(as, new Function
       
        () {            @Override            public B apply(A input) {                B b = new B();                b.setC(input.getC() / 0);                //...variables                return b;            }        }));    }}class A {    private int c;    //...variables    public int getC() {        return c;    }    public void setC(int c) {        this.c = c;    }}class B {    private int c;    //...variables    public int getC() {        return c;    }    public void setC(int c) {        this.c = c;    }}
       

执行结果： 

case1 startcase1 endcase2 start/ by zerocase2 end

case2比case1多了一步,在使用Lists.transform的时候将转换结果，用Lists.newArrayList 重新产生一个新的list。以确保function内的代码（比如调用远程方法，操作数据库等容易抛出异常的代码）立即被执行，而不是在要使用的时候执行，从而导致异常没有在预期的地方被捕获。