How to connect to database in Java
How to connect Java to MySQL database: first download and decompress the jar library file, and import the library file into the corresponding project; then add JDBC; then create tables and add data in the Mysql database ;Finally connect to the database and read the data.
Java requires a driver package to connect to the MySQL database. The latest version download address is: http://dev.mysql.com/downloads/connector/j/, unzip it Finally, get the jar library file, and then import the library file in the corresponding project.
Create a program that uses JDBC to connect to the database. Specific steps:
##1. Load the driver:
Import the database connection jar package, create a lib folder in the project directory, and place the downloaded JDBC in the folder, as shown in the following figure:
2. Add JDBC:
Right-click the project name, select Add JARs... in the Libraries tab in the java build path, and select the JDBC just added, as shown below:
3. Create tables and add data in the Mysql database.
CREATE TABLE emp( empno INT(4) PRIMARY KEY, ename VARCHAR(10), job VARCHAR(9), hiredate DATE, sal FLOAT(7,2) ) ;
4. Connect to the database and read data:
Database name: sqltestdbPacket name: empPort number: 3306Username: rootPassword: root
package sqldemo;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class main {
public static void main(String[] args) {
//声明Connection对象
Connection con;
//驱动程序名
String driver = "com.mysql.jdbc.Driver";
//URL指向要访问的数据库名mydata
String url = "jdbc:mysql://localhost:3306/sqltestdb";
//MySQL配置时的用户名
String user = "root";
//MySQL配置时的密码
String password = "123456";
//遍历查询结果集
try {
//加载驱动程序
Class.forName(driver);
//1.getConnection()方法，连接MySQL数据库！！
con = DriverManager.getConnection(url,user,password);
if(!con.isClosed())
System.out.println("Succeeded connecting to the Database!");
//2.创建statement类对象，用来执行SQL语句！！
Statement statement = con.createStatement();
//要执行的SQL语句
String sql = "select * from emp";
//3.ResultSet类，用来存放获取的结果集！！
ResultSet rs = statement.executeQuery(sql);
System.out.println("-----------------");
System.out.println("执行结果如下所示:");
System.out.println("-----------------");
System.out.println("姓名" + "\t" + "职称");
System.out.println("-----------------");
String job = null;
String id = null;
while(rs.next()){
//获取stuname这列数据
job = rs.getString("job");
//获取stuid这列数据
id = rs.getString("ename");
//输出结果
System.out.println(id + "\t" + job);
}
rs.close();
con.close();
} catch(ClassNotFoundException e) {
//数据库驱动类异常处理
System.out.println("Sorry,can`t find the Driver!");
e.printStackTrace();
} catch(SQLException e) {
//数据库连接失败异常处理
e.printStackTrace();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
System.out.println("数据库数据成功获取！！");
}
}
}The above is the detailed content of How to connect to database in Java. For more information, please follow other related articles on the PHP Chinese website!
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