java这么写增删改查
时间: 2024-01-18 08:17:13 浏览: 24
以下是Java中常见的增删改查操作的示例:
1. 增加数据:
```java
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
list.add("orange");
System.out.println(list); // 输出:[apple, banana, orange]
}
}
```
2. 删除数据:
```java
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
list.add("orange");
list.remove("banana");
System.out.println(list); // 输出:[apple, orange]
}
}
```
3. 修改数据:
```java
import java.util.ArrayList;import java.util.List;
public class Main {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
list.add("orange");
list.set(1, "grape");
System.out.println(list); // 输出:[apple, grape, orange]
}
}
```
4. 查询数据:
```java
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
list.add("orange");
String fruit = list.get(1);
System.out.println(fruit); // 输出:banana
}
}
```