19.JDBC和数据库访问.md

1.基本功能：

Java通过JDBC完成：

2.基本类型，通常用最后一种

3.JDBC简介

Java连接SQL例子：

参考：http://blog.chinaunix.net/uid-20726500-id-3876569.html

1.加载驱动

2.获取连接

3.连接实例：

定义：

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566 //DbManage.java

import java.sql.*;

public class DbManage {

public boolean InitDb(){

//初始化驱动

try {

//Class-SQL Server

Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

//Class-MySQL

//Class.forName("com.mysql.jdbc.Driver");

//Class-Oracle

//Class.forName("oracle.jdbc.driver.OracleDriver");

    } catch (ClassNotFoundException ec) {
        System.out.println("Error 1: ");
        System.out.println(ec.getMessage());
    }
    catch(Exception e){
        System.out.println("Error 2: ");
        System.out.println(e.getMessage());
    }

    //获取数据连接
    /*url的填写遵循各自规范
    --通用
    jdbc:subprotocol:other stuff,其中subprotocol之连接到特定的数据库,sutff不固定
    --mysql
    jdbc:mysql://hostname:port/databasename
    --oracle
    jdbc:oracle:thin:@hostname:port:databasename
    */
    //url
    String url = "jdbc:sqlserver://localhost:49838;databaseName=HAMSDb;IntegratedSecurity=True";
    //这里的端口要查看具体电脑,最后一个选项是用Windows验证的方式去连接到数据库服务器，不需要用户名和密码。官方推荐方式
    //String user = "";  //用户名
    //String pass = "";  //密码
    try {
        /*获取连接*/
        //标准的连接方式：DriverManager.getConnection(url, user, pass);
        Connection cn = DriverManager.getConnection(url);

        /*使用Statement操作数据库*/
        Statement st = cn.createStatement();
        //使用结果集查询表结果
        ResultSet resultQuery = st.executeQuery("select * from Devices");

// while(resultQuery.next()){

// System.out.println("Key: " + resultQuery.getInt(1) + "Id: " + resultQuery.getString(2));

// }//while

        //excute执行，但是这里的返回值boolean中的true和false不代表执行成功或者失败，表示是否有ResultSet对象返回，这点要注意！
        /*
        boolean b = st.execute("insert into aTest(ID, Name) values(3, 'ccc')");
        if (b) {
            System.out.println("有ResultSet对象返回，下面可以用ResultSet获取返回的结果集。");
        }
        */

    } catch (SQLException e) {
        System.out.println("Error 3: ");
        System.out.println(e.getMessage());
    }

    return true;
}

}

123456789101112 package com.company.project.jdbctest;

//Print.java

public class Print {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    //原始方法
    DbManage d = new DbManage();
    d.InitDb();
}

}

4.excuteUpdate语句

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980 package com.company.project.jdbctest;

//InitDataBase.java

import java.io.FileInputStream;

import java.io.InputStream;

import java.sql.Connection;

import java.sql.DriverManager;

import java.util.*;

public class InitDataBase {

//url

private String url;

public String getUrl() {

return url;

}

public void setUrl(String url) {

this.url = url;

}

//forClassName
private String forClassName;
public String getForClassName() {
    return forClassName;
}

public void setForClassName(String forClassName) {
    this.forClassName = forClassName;
}

//Connection
private Connection conn;
public Connection getConn() {
    return conn;
}
public void setConn(Connection conn) {
    this.conn = conn;
}
//构造
public InitDataBase(){};

//读取配置文件
public void ReadPropertyFile(){
    /*读取ini文件获取配置*/
    try{
        //读取配置文件
        Properties p = new Properties();
        p.load(new FileInputStream("Properties//mysqlconfig.ini"));

        //读取sqlClassForName
        setForClassName(p.getProperty("classForName"));

        //读取url
        setUrl(p.getProperty("url"));
    }
    catch(Exception e){
        e.getMessage();
        System.out.println("Load Properties Failed!");
    }
}

public void ConnectionSQL(){
    try {
        /*开始连接数据库*/
        ReadPropertyFile();

        //加载类
        Class.forName(getForClassName());
        //获取连接
        conn = DriverManager.getConnection(getUrl());
    } catch (ClassNotFoundException eof) {
        // TODO Auto-generated catch block
        eof.printStackTrace();
    }
    catch (Exception e){
        e.printStackTrace();
    }

}

}

12345678910111213141516171819202122232425 package com.company.project.jdbctest;

//ExcuteDDL.java

import java.sql.Connection;

import java.sql.SQLException;

import java.sql.Statement;

//执行DDL语句

public class ExcuteDDL {

public void createTable(String strSql){

//获取连接

InitDataBase idb = new InitDataBase();

idb.ConnectionSQL();

Connection cn = idb.getConn();

try {

Statement st = cn.createStatement();

st.executeUpdate(strSql);

    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.getMessage();
        System.out.println("ExcuteDDL Error !");
    }

}

}

12345678910111213 package com.company.project.jdbctest;

//Print.java

public class Print {

public static void main(String[] args) {
    //ExcuteDDL
    ExcuteDDL ed = new ExcuteDDL();
    //只执行一次
    //ed.createTable("create table excuteddl_test(ID int, NAME varchar(32))");
    System.out.println("create table successful!");
}

}

5.PreparedStatement语句

12345678910111213141516171819202122232425262728293031 package com.company.project.jdbctest;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.SQLException;

//PrepareStatementTest.java

public class PrepareStatementTest {

public void insertOneH(){

//获取连接

InitDataBase idb = new InitDataBase();

idb.ConnectionSQL();

Connection cn = idb.getConn();

//

String strSql = "insert into excuteddl_test(ID, NAME) values(?, ?)";

try {

PreparedStatement ps = cn.prepareStatement(strSql);

        //执行
        for (int i = 0; i < 100; i++) {
            ps.setString(1, i+"");
            ps.setString(2, "name"+i+"");
            ps.executeUpdate();
        }

    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

}

1234567891011 package com.company.project.jdbctest;

//Print.java

public class Print {

public static void main(String[] args) {
    PrepareStatementTest pst = new PrepareStatementTest();
    pst.insertOneH();
    System.out.println("create table successful!");
}

}

6.使用CallableStatement调用存储过程