比较器 Comparator

pom.xml

@@ -26,6 +26,12 @@
       <version>4.11</version>
       <scope>test</scope>
     </dependency>
+      <dependency>
+          <groupId>org.projectlombok</groupId>
+          <artifactId>lombok</artifactId>
+          <version>RELEASE</version>
+          <scope>compile</scope>
+      </dependency>
   </dependencies>
 
   <build>
@@ -63,5 +69,15 @@
         </plugin>
       </plugins>
     </pluginManagement>
+      <plugins>
+          <plugin>
+              <groupId>org.apache.maven.plugins</groupId>
+              <artifactId>maven-compiler-plugin</artifactId>
+              <configuration>
+                  <source>8</source>
+                  <target>8</target>
+              </configuration>
+          </plugin>
+      </plugins>
   </build>
 </project>

src/main/java/com/never/basic/ComparatorDemo.java

@@ -0,0 +1,59 @@
+package com.never.basic;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+
+public class ComparatorDemo {
+    public static void main(String[] args) {
+        Student s1 = new Student(4, 17, "张三");
+        Student s2 = new Student(1, 17, "张三");
+        Student s3 = new Student(3, 17, "张三");
+        Student s4 = new Student(8, 17, "张三");
+        Student s5 = new Student(6, 17, "张三");
+        System.out.println("--------Array------------");
+        Student[] arr = {s1,s2,s3,s4,s5};
+        for(int i = 0 ;i <arr.length; i++){
+            System.out.println(arr[i]);
+        }
+        System.out.println("--------------------");
+        Arrays.sort(arr,new IdComparator());
+        for(int i = 0 ;i <arr.length; i++){
+            System.out.println(arr[i]);
+        }
+
+        System.out.println("------ArrayList-------------");
+        ArrayList<Student> list = new ArrayList<>();
+        list.add(s1);
+        list.add(s2);
+        list.add(s3);
+        list.add(s4);
+        list.add(s5);
+        for(Student s: list){
+            System.out.println(s);
+        }
+        System.out.println("--------------------");
+        list.sort(new IdComparator());
+        for(Student s: list){
+            System.out.println(s);
+        }
+    }
+}
+class IdComparator implements Comparator<Student>{
+
+
+    @Override
+    public int compare(Student o1, Student o2) {
+        int res = 0;
+
+        if(o1.getId()<o2.getId()){
+            res = -1;
+        }else if (o1.getId()>o2.getId()){
+            res = 1;
+        }
+        else  if (o1.getId() == o2.getId()){
+            res = 0;
+        }
+        return res;
+    }
+}

src/main/java/com/never/basic/Student.java

@@ -0,0 +1,22 @@
+package com.never.basic;
+
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class Student {
+    private Integer id;
+    private Integer age;
+    private String name;
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "id=" + id +
+                ", age=" + age +
+                ", name='" + name + '\'' +
+                '}';
+    }
+}