高效 告别996，开启java高效编程之门 3-2传统方式处理业务逻辑

1　　　　重点

1.1　　　　对sort方法使用的理解

 

 

2　　　　代码演练

需求：

 根据第一章需求，女盆友提出需求
* 1 打印所有商品
* 2 图书类的商品一定给买
* 3 最贵的买两件
* 4 打印最贵的两件商品的名称和总价

测试类：

package com.imooc.zhangxiaoxi.stream;

import com.alibaba.fastjson.JSON;
import com.imooc.zhangxiaoxi.lambda.cart.CartService;
import com.imooc.zhangxiaoxi.lambda.cart.Sku;
import com.imooc.zhangxiaoxi.lambda.cart.SkuCategoryEnum;
import org.junit.Test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

/**
 * StreamVs
 *
 * @author 魏豆豆
 * @date 2020/4/7
 */
public class StreamVs {

    /**
     * 流和普通方法对比，本节应用普通方法
     *
     * 根据第一章需求，女盆友提出需求
     * 1    打印所有商品
     * 2    图书类的商品一定给买
     * 3    最贵的买两件
     * 4    打印最贵的两件商品的名称和总价
     */

    /**
     * 普通方法
     */
    @Test
    public void oldCartHandle(){
        //1 打印所有商品
        List<Sku> skuList = CartService.getSkuList();
        System.out.println("====================================================================================================");
        for(Sku sku: skuList){
            System.out.println(JSON.toJSONString(sku,true));
        }


        //2 排除图书类
        List<Sku> skuListNoBooks = new ArrayList<Sku>();
        for(Sku sku:skuList){
            if(!sku.getSkuCategory().equals(SkuCategoryEnum.BOOKS)){
                skuListNoBooks.add(sku);
            }
        }

        //3 最贵的买两件
        skuListNoBooks.sort(new Comparator<Sku>() {
            @Override
            public int compare(Sku o1, Sku o2) {
                if(o1.getTotalPrice()> o2.getTotalPrice()){
                    return -1;
                }else if(o1.getTotalPrice() < o2.getTotalPrice()){
                    return 1;
                }else{
                    return 0;
                }
            }
        });

        List<Sku> skuListPreTwo = new ArrayList<Sku>();
        for(int i = 0;i<2;i++){
            skuListPreTwo.add(skuListNoBooks.get(i));
        }

        System.out.println("====================================================================================================");
        Double totalPrice = 0.0;
        for(Sku sku:skuListPreTwo){
            totalPrice+=sku.getTotalPrice();
        }

        List<String> skuNameList = new ArrayList<String>();
        for (Sku sku:skuListPreTwo){
            skuNameList.add(sku.getSkuName());
        }


        System.out.println("商品总价为："+totalPrice);
        System.out.println("商品名称为："+ JSON.toJSONString(skuNameList,true));
    }



}

其他类参考2-3：

打印日志：

D:javajdkjdk9jdk-9+181_windows-x64_rijava-se-9-rijdk-9injava.exe -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:D:javadevolopKitideaanZhIntelliJ IDEA Community Edition 2018.1.4libidea_rt.jar=35416:D:javadevolopKitideaanZhIntelliJ IDEA Community Edition 2018.1.4in" -Dfile.encoding=UTF-8 -classpath "D:javadevolopKitideaanZhIntelliJ IDEA Community Edition 2018.1.4libidea_rt.jar;D:javadevolopKitideaanZhIntelliJ IDEA Community Edition 2018.1.4pluginsjunitlibjunit-rt.jar;D:javadevolopKitideaanZhIntelliJ IDEA Community Edition 2018.1.4pluginsjunitlibjunit5-rt.jar;F:xiangmu3Xin	est996	arget	est-classes;F:xiangmu3Xin	est996	argetclasses;F:xiangmu3Xin	est996libcomgoogleguavaguava28.2-jreguava-28.2-jre.jar;F:xiangmu3Xin	est996libcomgoogleguavafailureaccess1.0.1failureaccess-1.0.1.jar;F:xiangmu3Xin	est996libcomgoogleguavalistenablefuture9999.0-empty-to-avoid-conflict-with-guavalistenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar;F:xiangmu3Xin	est996libcomgooglecodefindbugsjsr3053.0.2jsr305-3.0.2.jar;F:xiangmu3Xin	est996liborgcheckerframeworkchecker-qual2.10.0checker-qual-2.10.0.jar;F:xiangmu3Xin	est996libcomgoogleerrorproneerror_prone_annotations2.3.4error_prone_annotations-2.3.4.jar;F:xiangmu3Xin	est996libcomgooglej2objcj2objc-annotations1.3j2objc-annotations-1.3.jar;F:xiangmu3Xin	est996libjunitjunit4.12junit-4.12.jar;F:xiangmu3Xin	est996liborghamcresthamcrest-core1.3hamcrest-core-1.3.jar;F:xiangmu3Xin	est996libcomalibabafastjson1.2.58fastjson-1.2.58.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit3 com.imooc.zhangxiaoxi.stream.StreamVs,oldCartHandle
====================================================================================================
{
    "skuCategory":"ELECTRONICS",
    "skuId":2020001,
    "skuName":"无人机",
    "skuPrice":999.0,
    "totalNum":1,
    "totalPrice":999.0
}
{
    "skuCategory":"CLOTHING",
    "skuId":2020002,
    "skuName":"T-shirt",
    "skuPrice":50.0,
    "totalNum":2,
    "totalPrice":100.0
}
{
    "skuCategory":"BOOKS",
    "skuId":2020003,
    "skuName":"人生的枷锁",
    "skuPrice":30.0,
    "totalNum":1,
    "totalPrice":30.0
}
{
    "skuCategory":"BOOKS",
    "skuId":2020004,
    "skuName":"老人与海",
    "skuPrice":20.0,
    "totalNum":1,
    "totalPrice":20.0
}
{
    "skuCategory":"BOOKS",
    "skuId":2020005,
    "skuName":"剑指高效编程",
    "skuPrice":288.0,
    "totalNum":1,
    "totalPrice":288.0
}
{
    "skuCategory":"CLOTHING",
    "skuId":2020006,
    "skuName":"大头皮鞋",
    "skuPrice":300.0,
    "totalNum":1,
    "totalPrice":300.0
}
{
    "skuCategory":"SPROTS",
    "skuId":2020007,
    "skuName":"杠铃",
    "skuPrice":2000.0,
    "totalNum":1,
    "totalPrice":2000.0
}
{
    "skuCategory":"ELECTRONICS",
    "skuId":2020008,
    "skuName":"ThinkPad",
    "skuPrice":5000.0,
    "totalNum":1,
    "totalPrice":5000.0
}
====================================================================================================
商品总价为：7000.0
商品名称为：[
    "ThinkPad",
    "杠铃"
]

Process finished with exit code 0