标签:version bsp plugins common package process span intellij jdk
1.1 reduce demo组成
1.2 准备数据
1.3 并行计算
测试类:
package com.imooc.zhangxiaoxi.stream;
import com.alibaba.fastjson.JSONObject;
import com.google.common.collect.Lists;
import org.junit.Test;
import java.util.ArrayList;
/**
* ReduceAndCollect
* 归约与汇总操作
* @author 魏豆豆
* @date 2020/5/7
*/
public class ReduceAndCollect {
@Test
/**
* 归约reduce Demo
* 需求:从一批订单中找到数量和总额,计算平均商品价格
*/
public void reduceTest(){
/**
* 订单对象
* @Data 注入SetGet方法 后边lombok会讲
* @AllArgsConstructor 注入传参方法
*/
class Order{
private Integer id; //订单编号
private Integer orderCount; //订单数量
private Double orderTotalPrice; //订单总价
public Order(Integer id, Integer orderCount, Double orderTotalPrice) {
this.id = id;
this.orderCount = orderCount;
this.orderTotalPrice = orderTotalPrice;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getOrderCount() {
return orderCount;
}
public void setOrderCount(Integer orderCount) {
this.orderCount = orderCount;
}
public Double getOrderTotalPrice() {
return orderTotalPrice;
}
public void setOrderTotalPrice(Double orderTotalPrice) {
this.orderTotalPrice = orderTotalPrice;
}
}
//准备数据
ArrayList<Order> list = Lists.newArrayList();
list.add(new Order(1,3,9.00));
list.add(new Order(1,2,100.00));
list.add(new Order(1,1,11.00));
/**
* reduce (初始逻辑,计算规则,并行计算规则)
* 需求:计算商品平均单价
*/
Order order = list.stream()
//并行计算
//.parallel()
.reduce(
//1 初始逻辑
new Order(0,0,0.00),
//2 计算规则
(Order order1,Order order2)->{
System.out.println("计算逻辑!!!");
Integer orderCount = order1.getOrderCount()+order2.getOrderCount();
Double orderPrice = order1.getOrderTotalPrice()+order2.getOrderTotalPrice();
return new Order(0,orderCount,orderPrice);
},
//3 并行计算
(Order order1,Order order2)->{
System.out.println("并行计算!!!");
Integer orderCount = order1.getOrderCount()+order2.getOrderCount();
Double orderPrice = order1.getOrderTotalPrice()+order2.getOrderTotalPrice();
return new Order(0,orderCount,orderPrice);
});
System.out.println(JSONObject.toJSONString(order,true));
}
}
打印日志:
D:\java\jdk\jdk9\jdk-9+181_windows-x64_ri\java-se-9-ri\jdk-9\bin\java.exe -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:D:\java\devolopKit\idea\anZh\IntelliJ IDEA Community Edition 2018.1.4\lib\idea_rt.jar=28296:D:\java\devolopKit\idea\anZh\IntelliJ IDEA Community Edition 2018.1.4\bin" -Dfile.encoding=UTF-8 -classpath "D:\java\devolopKit\idea\anZh\IntelliJ IDEA Community Edition 2018.1.4\lib\idea_rt.jar;D:\java\devolopKit\idea\anZh\IntelliJ IDEA Community Edition 2018.1.4\plugins\junit\lib\junit-rt.jar;D:\java\devolopKit\idea\anZh\IntelliJ IDEA Community Edition 2018.1.4\plugins\junit\lib\junit5-rt.jar;F:\xiangmu3\Xin\test996\target\test-classes;F:\xiangmu3\Xin\test996\target\classes;F:\xiangmu3\Xin\test996\lib\com\google\guava\guava\28.2-jre\guava-28.2-jre.jar;F:\xiangmu3\Xin\test996\lib\com\google\guava\failureaccess\1.0.1\failureaccess-1.0.1.jar;F:\xiangmu3\Xin\test996\lib\com\google\guava\listenablefuture\9999.0-empty-to-avoid-conflict-with-guava\listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar;F:\xiangmu3\Xin\test996\lib\com\google\code\findbugs\jsr305\3.0.2\jsr305-3.0.2.jar;F:\xiangmu3\Xin\test996\lib\org\checkerframework\checker-qual\2.10.0\checker-qual-2.10.0.jar;F:\xiangmu3\Xin\test996\lib\com\google\errorprone\error_prone_annotations\2.3.4\error_prone_annotations-2.3.4.jar;F:\xiangmu3\Xin\test996\lib\com\google\j2objc\j2objc-annotations\1.3\j2objc-annotations-1.3.jar;F:\xiangmu3\Xin\test996\lib\junit\junit\4.12\junit-4.12.jar;F:\xiangmu3\Xin\test996\lib\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;F:\xiangmu3\Xin\test996\lib\com\alibaba\fastjson\1.2.58\fastjson-1.2.58.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 com.imooc.zhangxiaoxi.stream.ReduceAndCollect,reduceTest
计算逻辑!!!
计算逻辑!!!
计算逻辑!!!
{
"id":0,
"orderCount":6,
"orderTotalPrice":120.0
}
Process finished with exit code 0
高效 告别996,开启java高效编程之门 3-23汇总操作实战案例
标签:version bsp plugins common package process span intellij jdk
原文地址:https://www.cnblogs.com/1446358788-qq/p/12861874.html