Java连接数据库中的MysqlUtil.java增删改查详解

￡神魔★判官ぃ 2023-10-06 21:49 8阅读 0赞

**目录**

举一个查询类GetCount.java

增删改查的MysqlUtil.java

--------------------

**四个类**

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16][]

**流程**

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

#### 举一个查询类GetCount.java ####

**这个是连接数据库的代码 （需要改成自己的）**

static String url = "jdbc:mysql://localhost:3306/car?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=false";
    	static String user = "账号";
    	static String password = "密码";

package com.sql;
    
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    
    import com.mysql.jdbc.Connection;
    import com.mysql.jdbc.Statement;
    
    
    
    public class GetCount {
    
    	static String url = "jdbc:mysql://localhost:3306/car?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=false";
    	static String user = "账号";
    	static String password = "密码";
    	
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		getCount();
    	}
    	
    	public static void getCount() {
    		int count = 0;
    		try {
    			// 1. 加载驱动
    			Class.forName("com.mysql.jdbc.Driver");
    			// 2.创建链接
    			Connection connection = (Connection) DriverManager.getConnection(url,user,password);
    			// 3.创建Statement对象
    			Statement statement = (Statement) connection.createStatement();
    			// 4.执行sql
    			String sql = "select  * from student";
    			ResultSet resultSet = statement.executeQuery(sql);
    			// 5. 结果
    			while (resultSet.next()) {
    				count += 1;
    			}
    			
    			if (resultSet !=null) {
    				resultSet.close();
    			}
    			
    			if (statement !=null) {
    				statement.close();
    			}
    			
    			if (connection !=null) {
    				connection.close();
    			}
    			
    			
    			
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    		System.out.println(count); 
    	}
    
    }

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 2][] 七条数据：

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_18_color_FFFFFF_t_70_g_se_x_16][]

#### 增删改查的MysqlUtil.java ####

package com.sql;
    
    
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    
    import com.mysql.jdbc.Connection;
    import com.mysql.jdbc.Statement;
    
    public class MysqlUtil {
    
    	static String url = "jdbc:mysql://localhost:3306/car?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=false";
    	static String user = "账号";
    	static String password = "密码";
    	
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		delete();
    	}
    	/*数据查询
    	 * 
    	 * 
    	 */
    	public static void search() {
    		try {
    			Class.forName("com.mysql.jdbc.Driver");
    			// 2.创建链接
    			Connection connection = (Connection) DriverManager.getConnection(url,user,password);
    						// 3.创建Statement对象
    			Statement statement = (Statement) connection.createStatement();
    						// 4.执行sql
    			String sql = "select * from student";
    			ResultSet resultSet = statement.executeQuery(sql);
    			while(resultSet.next()) {
    				String id = resultSet.getString("id");
    				String name = resultSet.getString("name");
    				String idCard = resultSet.getString("idCard");
    				String phone = resultSet.getString("phone");
    				System.out.println(id + " " + name + " " + idCard + " " + phone);
    				
    			}
    			if(resultSet!=null) {
    				resultSet.close();
    			}
    			if (statement !=null) {
    				statement.close();	
    			}
    			if (connection !=null) {
    				connection.close();
    			}
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    	}
    	
    	/*数据插入
    	 * 
    	 * 
    	 * 
    	 * */
    	private static int insert() {
    		// TODO Auto-generated method stub
    		int i =0;
    		try {
    			Class.forName("com.mysql.jdbc.Driver");
    			Connection connection =(Connection) DriverManager.getConnection(url,user,password);
    //			创建Statement对象
    			Statement statement =(Statement) connection.createStatement();
    			String sql ="insert into student(name,idCard,phone,height) values('苹果','12346','123456','184')";
    			statement.executeUpdate(sql);
    			
    			if (statement !=null) {
    				statement.close();	
    			}
    			if (connection !=null) {
    				connection.close();
    			}
    			i=1;
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return 1;
    	}
    	
    	public static int update() {
    		int  i = 0;
    		try {
    			Class.forName("com.mysql.jdbc.Driver");
    			Connection connection = (Connection) DriverManager.getConnection(url,user,password);
    			// 3.创建Statement对象
    			Statement statement = (Statement) connection.createStatement();
    			String sql = "update student set name = '香蕉'  where id =  1" ;
    			statement.executeUpdate(sql);
    			if (statement !=null) {
    				statement.close();
    			}
    			
    			if (connection !=null) {
    				connection.close();
    			}
    			
    			i = 1;
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return i;
    	}
    	
    	
    	public static int delete() {
    		int i=0;
    		try {
    			Class.forName("com.mysql.jdbc.Driver");
    			Connection connection = (Connection) DriverManager.getConnection(url,user,password);
    			// 3.创建Statement对象
    			Statement statement = (Statement) connection.createStatement();
    			String sql = "delete from student where id = 1" ;
    			statement.executeUpdate(sql);
    			if (statement !=null) {
    				statement.close();
    			}
    			
    			if (connection !=null) {
    				connection.close();
    			}
    			
    			i = 1;
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    		
    		return i ;
    		
    	}
    	
    }

**在main()中调用**

> 查询：调用search()函数；
> 
> 添加：调用insert()函数；
> 
> 更改：调用update()函数；
> 
> 删除：调用delete()函数；

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