使用DBUtils第三方工具类，实现MySQL数据库的增删改查
DBUtuls第三方工具类
使用到的有：
1.ResultSetHandler接口
结果集处理接口
2.QueryRunner类
完成数据库的增/删/改/查
3.DbUtils类
定义关闭资源与事物处理方法
1.自定义JDBC工具类与配置文件，实现数据库的连接
pro.properties配置文件
DriverPath=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mydatabase
username=root
password=123JDBCUtils 自定义工具类
package DBUitlsDemo;
import java.io.FileReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;
/**
* JDBC工具类
* Created by Aongi on 2017/5/1.
* Version 1.0
*/
public class JDBCUtils {
public JDBCUtils(){}
private static Connection CON;
static{
FileReader reader;
try {
String a=JDBCUtils.class.getResource("pro.properties").toString().substring(6);
reader = new FileReader(a);
//下面也是一种拿到文件路径的方式
//InputStream reader=JDBCUtils.class.getClassLoader().getResourceAsStream("pro.properties");
Properties pro = new Properties();
pro.load(reader);
reader.close();
Class.forName(pro.getProperty("DriverPath"));
CON= DriverManager.getConnection(pro.getProperty("url"),pro.getProperty("username"),pro.getProperty("password"));
} catch (Exception e) {
throw new RuntimeException("连接数据库失败！");
}
}
/*
*链接数据库操作，返回Connection对象
*/
public static Connection getConnection(){
return CON;
}
}
2.定义与数据库匹配的实体类：Students
1.私有变量对应数据库的列
2.必须有空参构造方法
3.get/set方法
4.重写toString方法
package DBUitlsDemo;
/**
* Created by Aongi on 2017/5/2.
* Version 1.0
*/
public class Students {
private Integer uid;
private String uname;
private String uaddress;
private Integer age;
public Students(Integer uid, String uname, String uaddress, Integer age) {
this.uid = uid;
this.uname = uname;
this.uaddress = uaddress;
this.age = age;
}
public Students(){}
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public String getUname() {
return uname;
}
public void setUname(String uname) {
this.uname = uname;
}
public String getUaddress() {
return uaddress;
}
public void setUaddress(String uaddress) {
this.uaddress = uaddress;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return uid + "\t" + uname + "\t" + uaddress + "\t" + age;
}
}3.实现增删改查类：QueryRunnerDemo
1.增加/修改/删除，写到了一个方法里，传入两个参数
String sql SQL语句
Object[] params SQL语句中的？占位符数组集
2.查询数据-----8中结果集处理方式
1.ArrayHandler 查询------取单行遍历
2.ArrayListHandler 查询------取多行遍历
3.BeanHandler 查询------取单行遍历
4.BeanListHandler 查询------取多行遍历
5.MapHandler 查询------取单行遍历
6.MapListHandler 查询------取多行遍历
7.ColumnListHandler 查询列数据
8.ScalarHandler 查询单个数据
package DBUitlsDemo;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.*;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
/**
* Created by Aongi on 2017/5/2.
* Version 1.0
*/
public class QueryRunnerDemo {
private static Connection CON = JDBCUtils.getConnection();
//数据的增加，修改，删除
public static void addUpdataDelete(String sql, Object[] params) throws Exception {
QueryRunner qr = new QueryRunner();
int i = qr.update(CON, sql, params);
DbUtils.close(CON);
System.out.println(i + "条语句执行成功");
}
//main方法
public static void main(String[] args) throws Exception {
/**
* 增加数据
*/
// String sql="INSERT INTO users (uname,uaddress,age) VALUES (?,?,?);";
// Object[] params={"小李","guangzhou","30"};
// addUpdataDelete(sql,params);
/**
* 修改数据
*/
// String sql="UPDATE users SET uname=?,uaddress=?,age=? WHERE uid=?;";
// Object[] params={"小赵","chengdu","28","10"};
// addUpdataDelete(sql,params);
/**
* 删除数据
*/
// String sql="DELETE FROM users WHERE uid=?;";
// Object[] params={"10"};
// addUpdataDelete(sql,params);
/**
* 查询数据---8种结果集处理方式
*/
select();
}
/**
* 多种方式---数据的查询
*/
public static void select() throws Exception {
arrayHandler();//ArrayHandler查询
System.out.println("--------------------------------------------------");
arrayListHandler();//ArrayListHandler查询
System.out.println("--------------------------------------------------");
beanHandler();//BeanHandler查询
System.out.println("--------------------------------------------------");
beanListHandler();//BeanListHandler查询
System.out.println("--------------------------------------------------");
columnListHandler();//ColumnListHandler查询
System.out.println("--------------------------------------------------");
mapHandler();//MapHandler查询
System.out.println("--------------------------------------------------");
mapListHandler();//MapListHandler查询
System.out.println("--------------------------------------------------");
scalarHandler();//ScalarHandler查询
}
/**
* ArrayHandler查询-----取一行遍历
*/
public static void arrayHandler() throws SQLException {
QueryRunner qr = new QueryRunner();
String sql = "SELECT * FROM users WHERE uid=4;";
Object[] data = qr.query(CON, sql, new ArrayHandler());
for (Object obj : data) {
System.out.print(obj + "\t");
}
System.out.println();
}
/**
* ArrayListHandler查询------取多行遍历
*/
public static void arrayListHandler() throws SQLException {
QueryRunner qr = new QueryRunner();
String sql = "SELECT * FROM users WHERE uid>4;";
List data = qr.query(CON, sql, new ArrayListHandler());
for (Object[] obj : data) {
for (Object o : obj) {
System.out.print(o + "\t");
}
System.out.println();
}
}
/**
* BeanHandler查询------取一行遍历
* 实体类必须要有空参构造方法
*/
public static void beanHandler() throws SQLException {
QueryRunner qr = new QueryRunner();
String sql = "SELECT * FROM users WHERE uid=4;";
Students stu = qr.query(CON, sql, new BeanHandler(Students.class));
System.out.println(stu);
}
/**
* BeanListHandler查询------取多行遍历
* 实体类必须要有空参构造方法
*/
public static void beanListHandler() throws SQLException {
QueryRunner qr = new QueryRunner();
String sql = "SELECT * FROM users WHERE uid>4;";
List stulist = qr.query(CON, sql, new BeanListHandler(Students.class));
for (Students stu : stulist) {
System.out.println(stu);
}
}
/**
* ColumnListHandler查询列数据
* 注意：sql查询语句里查询的数据必须包含你想要查询的列数据
*/
public static void columnListHandler() throws SQLException{
QueryRunner qr = new QueryRunner();
String sql = "SELECT * FROM users;";
List