jdbc数据库连接之jdbcUtils工具类抽取

 JDBC数据库连接
1.准备数据库
　初始化数据库和表:
        CREATE DATABASE day07;
        USE day07;    
        
        create table category(
            cid varchar(20) primary key,
            cname varchar(20)
        );
        
        insert into category values(‘c001‘,‘电器‘);
        insert into category values(‘c002‘,‘服饰‘);
        insert into category values(‘c003‘,‘化妆品‘);
        insert into category values(‘c004‘,‘书籍‘);
　　db.properties
　　jdbc.driverClass=com.mysql.jdbc.Driver
　　jdbc.url=jdbc:mysql://localhost:3306/test
　　jdbc.username=root
　　jdbc.password=123
2.新建一个测试类
3.对jdbc进行抽取工具类 

package com.demo.jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ResourceBundle;



public class jdbcUtils {
    public static final String DRIVERCLASS;
    public static final String URL;
    public static final String USERNAME;
    public static final String PASSWORD;
    static{
　　　　　　//加载配置文件
        ResourceBundle bundle = ResourceBundle.getBundle("db");
        DRIVERCLASS= bundle.getString("jdbc.driverClass");
        URL = bundle.getString("jdbc.url");
        USERNAME = bundle.getString("jdbc.username");
        PASSWORD = bundle.getString("jdbc.password");
        
    }
    //静态方法加载驱动
    static{
        try {
            Class.forName(DRIVERCLASS);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }
    //获取连接
    public static Connection getConnection() throws Exception{
        return DriverManager.getConnection(URL,USERNAME,PASSWORD);
        
    }
    //释放资源
    public static void closeReasoure(Connection conn,Statement st,ResultSet rs ){
        closeResultSet(rs);
        closeStatement(st);
        closeConn(conn);
            
        
    }
    
    
    /**
     * 释放连接
     * @param conn 连接
     */
    public static void closeConn(Connection conn){
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                conn=null;
            }
        }
    }
    

    
    /**
     * 释放语句执行者
     * @param st  执行者
     */
    public static void closeStatement(Statement st){
        if(st != null){
            try {
                st.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                st=null;
            }
        }
    }
    
    /*
     * 
     * 
     * @param rs 
     * 
     * */
    
    /**
     * 释放结果集
     * @param rs 结果集
     */
    public static void closeResultSet(ResultSet rs){
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                rs=null;
            }
        }
    }
}

 1 package com.demo.jdbc;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8 import java.util.ResourceBundle;
 9 
10 
11 
12 public class jdbcUtils {
13 
14     //获取连接
15     public static Connection getConnection() throws Exception{
16         
17         ResourceBundle bundle = ResourceBundle.getBundle("db");
18         String driverClass = bundle.getString("jdbc.driverClass");
19         String url = bundle.getString("jdbc.url");
20         String username = bundle.getString("jdbc.username");
21         String password = bundle.getString("jdbc.password");
22         
23         Class.forName(driverClass);
24         Connection conn = DriverManager.getConnection(url,username,password);
25         return conn;
26         
27     }
28     //释放资源
29     public static void closeReasoure(Connection conn,Statement st,ResultSet rs ){
30         closeResultSet(rs);
31         closeStatement(st);
32         closeConn(conn);
33             
34         
35     }
36     
37     
38     /**
39      * 释放连接
40      * @param conn 连接
41      */
42     public static void closeConn(Connection conn){
43         if(conn != null){
44             try {
45                 conn.close();
46             } catch (SQLException e) {
47                 // TODO Auto-generated catch block
48                 e.printStackTrace();
49             }finally{
50                 conn=null;
51             }
52         }
53     }
54     
55 
56     
57     /**
58      * 释放语句执行者
59      * @param st  执行者
60      */
61     public static void closeStatement(Statement st){
62         if(st != null){
63             try {
64                 st.close();
65             } catch (SQLException e) {
66                 // TODO Auto-generated catch block
67                 e.printStackTrace();
68             }finally{
69                 st=null;
70             }
71         }
72     }
73     
74     /*
75      * 
76      * 
77      * @param rs 
78      * 
79      * */
80     
81     /**
82      * 释放结果集
83      * @param rs 结果集
84      */
85     public static void closeResultSet(ResultSet rs){
86         if(rs != null){
87             try {
88                 rs.close();
89             } catch (SQLException e) {
90                 // TODO Auto-generated catch block
91                 e.printStackTrace();
92             }finally{
93                 rs=null;
94             }
95         }
96     }
97 }

 1 package com.demo.jdbc;
 2 
 3 import static org.junit.Assert.*;
 4 
 5 import java.sql.Connection;
 6 import java.sql.DriverManager;
 7 import java.sql.PreparedStatement;
 8 import java.sql.ResultSet;
 9 
10 import org.junit.Test;
11 
12 import com.mysql.jdbc.Driver;
13 
14 /**
15  * @author Administrator
16  *
17  */
18 /**
19  * @author Administrator
20  *
21  */
22 /**
23  * @author Administrator
24  *
25  */
26 public class hello {
27     @Test
28     public void testjdbc() throws Exception {
29         //注册驱动
30         Class.forName("com.mysql.jdbc.Driver");
31         //获取连接对象
32         Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","123");
33         //编写SQL语句
34         String sql =  "select * from category";
35         //创建执行者对象
36         PreparedStatement prepareStatement = con.prepareStatement(sql);
37         //设置参数
38         
39         //执行sql
40         ResultSet rs = prepareStatement.executeQuery();
41         //处理结果集
42         while(rs.next()){
43             System.out.println(rs.getString("cid")+"::"+rs.getString("cname"));
44         }
45         //释放资源
46         rs.close();
47         prepareStatement.close();
48         con.close();
49         
50     }
51     
52     //插入数据（）
53     @Test
54     public void testjdbcUtils(){
55             Connection conn=null;
56             ResultSet rs=null;
57             PreparedStatement st = null;
58             
59             //获取连接
60          try {
61             conn= jdbcUtils.getConnection();
62         
63          String sql = "insert into category values(?,?)";
64          
65          st = conn.prepareStatement(sql);
66          
67          st.setString(1,"c005");
68          st.setString(2, "户外");
69          
70          int i=st.executeUpdate();
71         
72          if(i==1){
73              System.out.println("success");
74          }else{
75              System.out.println("fail");
76          }
77             
78     } catch (Exception e) {
79             
80     e.printStackTrace();
81 
82 }finally{
83         //释放资源
84         jdbcUtils.closeReasoure(conn, st, rs);
85     }
86     }
87 }