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); } }
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