1

.gitignore

@@ -0,0 +1,33 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

pom.xml

@@ -0,0 +1,76 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.example</groupId>
+    <artifactId>day19</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>day19</name>
+    <description>Demo project for Spring Boot</description>
+    <properties>
+        <java.version>1.8</java.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <spring-boot.version>2.6.13</spring-boot.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+                <version>${spring-boot.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                    <encoding>UTF-8</encoding>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <version>${spring-boot.version}</version>
+                <configuration>
+                    <mainClass>com.example.demo.Day19Application</mainClass>
+                    <skip>true</skip>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>repackage</id>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

src/main/java/com/example/demo/Day19Application.java

@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Day19Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Day19Application.class, args);
+    }
+
+}

src/main/java/com/example/demo/test/Student.java

@@ -0,0 +1,17 @@
+package com.example.demo.test;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class Student {
+    private Integer id;
+    private String name;
+    private String clazz;
+    private Double score;
+}

src/main/java/com/example/demo/test/Test.java

@@ -0,0 +1,54 @@
+package com.example.demo.test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.OptionalDouble;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.Stream;
+
+public class Test {
+
+    public static void main(String[] args) {
+
+
+        //创建对象
+        Student student1 = new Student(1, "张三", "语文", 80.0);
+        Student student2 = new Student(2, "张三", "数学", 81.5);
+        Student student3 = new Student(3, "李四", "语文", 90.0);
+        Student student4 = new Student(4, "王五", "语文", 87.5);
+        Student student5 = new Student(5, "王五", "数学", 98.0);
+        List<Student> list = new ArrayList<>();
+        //添加集合
+        list.add(student1);
+        list.add(student2);
+        list.add(student3);
+        list.add(student4);
+        list.add(student5);
+
+
+        //通过steam循环计算
+        List<Student> collect = list.stream().map(student -> {
+            int c = 0;
+            double sum = 0.0;
+            for (Student stu : list) {
+                if (stu.getName().equals(student.getName())) {
+                    sum += stu.getScore();
+                    c++;
+                }
+            }
+            double avg = sum / c;
+            Student build = Student.builder().name(student.getName())
+                    .score(avg).build();
+            return build;
+
+        }).distinct().collect(Collectors.toList());
+        for (Student student : collect) {
+            System.out.println(student.getName()+" "+student.getScore());
+        }
+
+
+    }
+
+
+}

src/test/java/com/example/demo/Day19ApplicationTests.java

@@ -0,0 +1,13 @@
+package com.example.demo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class Day19ApplicationTests {
+
+    @Test
+    void contextLoads() {
+    }
+
+}