摘要:本文主要介绍了编程语言的DButils工具类对数据库增删改查操作,通过具体的编程案例分析,让我们从中获得很大的帮助,希望对大家学习编程语言有所帮助。
本文主要介绍了编程语言的DButils工具类对数据库增删改查操作,通过具体的编程案例分析,让我们从中获得很大的帮助,希望对大家学习编程语言有所帮助。
DBUtils工具类对数据库进行增删改查操作:
实体类:User.java
package com.iotek.javabean;
public class User {
private Integer id;
private String sname;
private Integer age;
public User() {
// TODO Auto-generated constructor stub
}
public User(Integer id, String sname, Integer age) {
super();
this.id = id;
this.sname = sname;
this.age = age;
}
public User(String sname, Integer age) {
super();
this.sname = sname;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "User [id=" + id + ", sname=" + sname + ", age=" + age + "]";
}
}db.properties属于性文件
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/stu
user=root
password=root
连接数据库的返回Connetion对象:
DBUtils.java
package com.iotek.dbuitls;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
import org.junit.Test;
public class DBUtils {
private static String driver;
private static String url;
private static String user;
private static String password;
private static Properties prop;
static {
// 读取配置文件(只读取一次)
prop = new Properties();
try {
// 读取配置文件
prop.load(Thread.currentThread().getContextClassLoader()
.getResourceAsStream("db.properties"));
driver = prop.getProperty("driver");
url = prop.getProperty("url");
user = prop.getProperty("user");
password = prop.getProperty("password");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 获取连接数据库的对象
*
* @return
*/
@Test
public static Connection getConn() {
try {
// 注册驱动
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println("连接成功" + conn);
return conn;
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
public static void main(String[] args) {
getConn();
}
}
Dbutils操作数据库操作:
package com.iotek.dbuitls;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import org.junit.Test;
import com.iotek.javabean.User;
public class DbutilsCrud {
@Test
public void insert() throws SQLException{
Connection conn=DBUtils.getConn();
QueryRunner qr=new QueryRunner();
String sql="insert into tb_user(sname,age) values(?,?)";
Object[] params={"lv",26};
// qr.update(conn, sql, "liayin",25);
int a= qr.update(conn, sql, params);
System.out.println("a=="+a);
}
@Test
public void getUserById() throws SQLException{
Connection conn=DBUtils.getConn();
QueryRunner qr=new QueryRunner();
String sql="select * from tb_user where id=?";
// ResultSetHandler父接口
User user=qr.query(conn, sql, 1, new BeanHandler(User.class));
System.out.println(user);
}
@Test
public void getUserList() throws SQLException{
Connection conn=DBUtils.getConn();
QueryRunner qr=new QueryRunner();
String sql="select * from tb_user";
// ResultSetHandler父接口
Listusers=qr.query(conn, sql, new BeanListHandler(User.class));
System.out.println(users);
}
/* 把一行转换成map*/
@Test
public void getUserMap() throws SQLException{
Connection conn=DBUtils.getConn();
QueryRunner qr=new QueryRunner();
String sql="select * from tb_user where id=?";
// ResultSetHandler父接口
Map map=qr.query(conn, sql, new MapHandler(),1);
System.out.println(map);
}
/* 多行处理,把每一行转换成一个map*/
@Test
public void getUsersMap() throws SQLException{
Connection conn=DBUtils.getConn();
QueryRunner qr=new QueryRunner();
String sql="select * from tb_user";
// ResultSetHandler父接口
List mapList=qr.query(conn, sql, new MapListHandler());
System.out.println(mapList);
}
/*单行单列 返回一个值*/
@Test
public void getCountUser() throws SQLException{
Connection conn=DBUtils.getConn();
QueryRunner qr=new QueryRunner();
String sql="select count(1) from tb_user";
// ResultSetHandler父接口
Number cnt=qr.query(conn, sql, new ScalarHandler());
System.out.println(cnt);
}
}本文由职坐标整理并发布,希望对同学们有所帮助。了解更多详情请关注职坐标编程语言频道!
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