【JDBC】工具类的抽取

jdbc.properties属性文件

driverclass=com.mysql.jdbc.driver
url=jdbc:mysql:///jdbctest
username=root
password=1234

jdbcutils.java工具类

package com.imooc.jdbc.utils;

import java.io.ioexception;
import java.io.inputstream;
import java.sql.connection;
import java.sql.drivermanager;
import java.sql.resultset;
import java.sql.sqlexception;
import java.sql.statement;
import java.util.properties;

/**
 * jdbc的工具类
 * @author jt
 *
 */
public class jdbcutils {
    private static final string driverclass;
    private static final string url;
    private static final string username;
    private static final string password;
    
    static{
        // 加载属性文件并解析：
        properties props = new properties();
        // 如何获得属性文件的输入流？
        // 通常情况下使用类的加载器的方式进行获取：
        inputstream is = jdbcutils.class.getclassloader().getresourceasstream("jdbc.properties");
        try {
            props.load(is);
        } catch (ioexception e) {
            e.printstacktrace();
        }
        
        driverclass = props.getproperty("driverclass");
        url = props.getproperty("url");
        username = props.getproperty("username");
        password = props.getproperty("password");
    }

    /**
     * 注册驱动的方法
     * @throws classnotfoundexception 
     */
    public static void loaddriver() throws classnotfoundexception{
        class.forname(driverclass);
    }
    
    /**
     * 获得连接的方法:
     * @throws sqlexception 
     */
    public static connection getconnection() throws exception{
        loaddriver();
        connection conn = drivermanager.getconnection(url, username, password);
        return conn;
    }
    
    /**
     * 资源释放
     */
    public static void release(statement stmt,connection conn){
        if(stmt != null){
            try {
                stmt.close();
            } catch (sqlexception e) {
                e.printstacktrace();
            }
            stmt = null;
        }
        if(conn != null){
            try {
                conn.close();
            } catch (sqlexception e) {
                e.printstacktrace();
            }
            conn = null;
        }
    }
    
    public static void release(resultset rs,statement stmt,connection conn){
        if(rs!= null){
            try {
                rs.close();
            } catch (sqlexception e) {
                e.printstacktrace();
            }
            rs = null;
        }
        if(stmt != null){
            try {
                stmt.close();
            } catch (sqlexception e) {
                e.printstacktrace();
            }
            stmt = null;
        }
        if(conn != null){
            try {
                conn.close();
            } catch (sqlexception e) {
                e.printstacktrace();
            }
            conn = null;
        }
    }
}

jdbcdemo3.java测试

package com.imooc.jdbc.demo1;

import java.sql.connection;
import java.sql.statement;

import org.junit.test;

import com.imooc.jdbc.utils.jdbcutils;

public class jdbcdemo3 {

    @test
    // 保存记录
    public void demo1(){
        connection conn = null;
        statement stmt  = null;
        try{
            // 获得连接:
            conn = jdbcutils.getconnection();
            // 创建执行sql语句的对象
            stmt = conn.createstatement();
            // 编写sql:
            string sql = "insert into user values (null,'ggg','123','小六')";
            // 执行sql:
            int num = stmt.executeupdate(sql);
            if(num > 0){
                system.out.println("保存成功!");
            }
        }catch(exception e){
            e.printstacktrace();
        }finally{
            // 释放资源:
            jdbcutils.release(stmt, conn);
        }
    }
}