JDBC操作

一、插入数据

package TestJDBC;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

import com.sun.jdi.connect.spi.Connection;

public class TestJDBC {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		 try {
	            Class.forName("com.mysql.cj.jdbc.Driver");
	  
	            java.sql.Connection c = DriverManager
	                    .getConnection(
	                            "jdbc:mysql://127.0.0.1:3306/mysql?characterEncoding=UTF-8",
	                            "root", "密码");
	  
	            System.out.println("连接成功，获取连接对象： " + c);
	            
	            Statement s = c.createStatement();
	            //System.out.println("获Statement对象： " + s);
	            String sql =  "insert into hero values(2,"+"'lax'"+","+50+","+313.0f+")";
	            s.execute(sql);
	            System.out.println("执行插入语句成功！");
	  
	        } catch (ClassNotFoundException e) {
	            e.printStackTrace();
	        } catch (SQLException e) {
	            // TODO Auto-generated catch block
	            e.printStackTrace();
	        }
	  
	    }

}

　二、关闭连接

package jdbc;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
 
public class TestJDBC {
    public static void main(String[] args) {
 
        Connection c = null;
        Statement s = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
 
            c = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/how2java?characterEncoding=UTF-8", "root",
                    "admin");
 
            s = c.createStatement();
 
            String sql = "insert into hero values(null," + "'提莫'" + "," + 313.0f + "," + 50 + ")";
 
            s.execute(sql);
 
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            // 数据库的连接时有限资源，相关操作结束后，养成关闭数据库的好习惯
            // 先关闭Statement
            if (s != null)
                try {
                    s.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            // 后关闭Connection
            if (c != null)
                try {
                    c.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
 
        }
 
    }
}

　三、插入数据

在Hero表中插入100条数据，代码如下：

package TestJDBC;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

import com.sun.jdi.connect.spi.Connection;

public class TestJDBC {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		 try {
	            Class.forName("com.mysql.cj.jdbc.Driver");
	  
	            java.sql.Connection c = DriverManager
	                    .getConnection(
	                            "jdbc:mysql://127.0.0.1:3306/mysql?characterEncoding=UTF-8",
	                            "root", "密码");
	  
	            System.out.println("连接成功，获取连接对象： " + c);
	            
	            Statement s = c.createStatement();
	            //System.out.println("获Statement对象： " + s);
	            for(int i =3;i<103;i++) {
	            	String sql = "insert into Hero values("+i+","+"'hero"+i+"'"+","+50+","+313.0f+")";
		            s.execute(sql);
	            }
	            
	  
	        } catch (ClassNotFoundException e) {
	            e.printStackTrace();
	        } catch (SQLException e) {
	            // TODO Auto-generated catch block
	            e.printStackTrace();
	        }
	  
	    }

}

　　在navicat中观察插入结果

 

 在插入中要注意SQL语句的编写，字符串要用双引号引起来，变量和常量不需要。