Java如何限制MySQL查询结果？
package org.nhooo.example.jdbc;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class SqlLimitExample {
private static final String URL = "jdbc:mysql://localhost/nhooo";
private static final String USERNAME = "root";
private static final String PASSWORD = "";
public static void main(String[] args) {
try (Connection connection =
DriverManager.getConnection(URL, USERNAME, PASSWORD)) {
//创建PreparedStatement以从数据库获取所有数据。
String query = "select count(*) from products";
PreparedStatement ps = connection.prepareStatement(query);
ResultSet result = ps.executeQuery();
int total = 0;
while (result.next()) {
total = result.getInt(1);
}
System.out.println("Total number of data in database: " +
total + "\n");
//仅对前5条记录创建PreparedStatement。
query = "select * from products limit 5";
ps = connection.prepareStatement(query);
result = ps.executeQuery();
System.out.println("Result fetched with specified limit 5");
System.out.println("====================================");
while (result.next()) {
System.out.println("id:" + result.getInt("id") +
", code:" + result.getString("code") +
", name:" + result.getString("name") +
", price:" + result.getString("price"));
}
//创建PreparedStatement以从第4个获取数据
//记录（记住第一个记录为0）并受限制
//到3条记录。
query = "select * from products limit 3, 3";
ps = connection.prepareStatement(query);
result = ps.executeQuery();
System.out.println("\nResult fetched with specified limit 3, 3");
System.out.println("====================================");
while (result.next()) {
System.out.println("id:" + result.getInt("id") +
", code:" + result.getString("code") +
", name:" + result.getString("name") +
", price:" + result.getString("price"));
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}我们程序的示例结果是：
Total number of data in database: 9 Result fetched with specified limit 5 ==================================== id:1, code:P0000001, name:UML Distilled 3rd Edition, price:25.00 id:3, code:P0000003, name:PHP Programming, price:20.00 id:4, code:P0000004, name:Longman Active Study Dictionary, price:40.00 id:5, code:P0000005, name:Ruby on Rails, price:24.00 id:6, code:P0000006, name:Championship Manager, price:0.00 Result fetched with specified limit 3, 3 ==================================== id:5, code:P0000005, name:Ruby on Rails, price:24.00 id:6, code:P0000006, name:Championship Manager, price:0.00 id:7, code:P0000007, name:Transport Tycoon Deluxe, price:0.00
Maven依赖
<!-- https://search.maven.org/remotecontent?filepath=mysql/mysql-connector-java/8.0.17/mysql-connector-java-8.0.17.jar -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.17</version>
</dependency>