jdk8 stream example

Author: aillamsun

pom.xml

@@ -34,12 +34,30 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>
 		</dependency>
+
+
+
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<version>1.16.16</version><!--$NO-MVN-MAN-VER$-->
+		</dependency>
+
+
+
 		<dependency>
 			<groupId>com.google.guava</groupId>
 			<artifactId>guava</artifactId>
 			<version>22.0</version>
 		</dependency>
 
+		<dependency>
+			<groupId>com.alibaba</groupId>
+			<artifactId>fastjson</artifactId>
+			<version>1.2.30</version>
+		</dependency>
+
+
 	</dependencies>
 
 	<build>

src/main/java/com/sung/java8/lambda/Apple.java

@@ -0,0 +1,34 @@
+package com.sung.java8.lambda;
+
+import lombok.Data;
+
+/**
+ * Created by sungang on 2017/8/15.
+ */
+@Data
+public class Apple {
+    /** 编号 */
+    private long id;
+
+    /** 颜色 */
+    private Color color;
+
+    /** 重量 */
+    private float weight;
+
+    /** 产地 */
+    private String origin;
+
+    public Apple() {
+    }
+
+    public Apple(long id, Color color, float weight, String origin) {
+        this.id = id;
+        this.color = color;
+        this.weight = weight;
+        this.origin = origin;
+    }
+
+
+
+}

src/main/java/com/sung/java8/lambda/AppleFilter.java

@@ -0,0 +1,16 @@
+package com.sung.java8.lambda;
+
+/**
+ * Created by sungang on 2017/8/15.
+ */
+public interface AppleFilter {
+
+    /**
+     * 筛选条件抽象
+     *
+     * @param apple
+     * @return
+     */
+    boolean accept(Apple apple);
+
+}

src/main/java/com/sung/java8/lambda/Color.java

@@ -0,0 +1,10 @@
+package com.sung.java8.lambda;
+
+
+/**
+ * Created by sungang on 2017/8/15.
+ */
+public enum  Color {
+    GREEN,
+    RED
+}

src/main/java/com/sung/java8/lambda/TestMain.java

@@ -0,0 +1,88 @@
+package com.sung.java8.lambda;
+
+import com.alibaba.fastjson.JSON;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by sungang on 2017/8/15.
+ */
+public class TestMain {
+
+
+
+
+
+    public static void main(String[] args) {
+        List<Apple> apples = new ArrayList<Apple>() {
+            {
+                add(new Apple(1, Color.GREEN, 100, "四川"));
+                add(new Apple(2, Color.RED, 101, "广西"));
+                add(new Apple(3, Color.GREEN, 120, "陕西"));
+            }
+        };
+        // 筛选苹果
+        List<Apple> filterApples = filterApplesByAppleFilter(apples, new AppleFilter() {
+            @Override
+            public boolean accept(Apple apple) {
+                // 筛选重量大于100g的红苹果
+                return Color.RED.equals(apple.getColor()) && apple.getWeight() > 100;
+            }
+        });
+
+        System.out.println(JSON.toJSONString(filterApples));
+    }
+
+    /**
+     * 用户最开始的需求可能只是简单的希望能够通过程序筛选出绿色的苹果，于是我们可以很快的通过程序实现：
+     *
+     * @param apples
+     * @return
+     */
+    public static List<Apple> filterGreenApples(List<Apple> apples) {
+        List<Apple> filterApples = new ArrayList<>();
+        for (final Apple apple : apples) {
+            if (Color.GREEN.equals(apple.getColor())) {
+                filterApples.add(apple);
+            }
+        }
+        return filterApples;
+    }
+
+
+    /**
+     * 将筛选条件封装成接口
+     *
+     * @param apples
+     * @param filter
+     * @return
+     */
+    public static List<Apple> filterApplesByAppleFilter(List<Apple> apples, AppleFilter filter) {
+        List<Apple> filterApples = new ArrayList<>();
+        for (final Apple apple : apples) {
+            if (filter.accept(apple)) {
+                filterApples.add(apple);
+            }
+        }
+        return filterApples;
+    }
+
+
+
+    @Test
+    public void test1(){
+        List<Apple> apples = new ArrayList<Apple>() {
+            {
+                add(new Apple(1, Color.GREEN, 100, "四川"));
+                add(new Apple(2, Color.RED, 101, "广西"));
+                add(new Apple(3, Color.GREEN, 120, "陕西"));
+            }
+        };
+        // 筛选苹果
+        List<Apple> filterApples = filterApplesByAppleFilter(apples,(Apple apple) -> Color.RED.equals(apple.getColor()) && apple.getWeight() >= 100);
+        //()->xxx   ()里面就是方法参数，xxx是方法实现
+        System.out.println(JSON.toJSONString(filterApples));
+    }
+}

src/main/java/com/sung/java8/stream/Student.java

@@ -0,0 +1,36 @@
+package com.sung.java8.stream;
+
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * Created by sungang on 2017/8/15.
+ */
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class Student {
+
+    /**
+     * 学号
+     */
+    private long id;
+    private String name;
+    private int age;
+    /**
+     * 年级
+     */
+    private int grade;
+    /**
+     * 专业
+     */
+    private String major;
+    /**
+     * 学校
+     */
+    private String school;
+
+
+}