java的JDBC连接的万能版总结（dao模式）

                                                       java的JDBC连接数据库Mysql，sqlserver, Oracle dao模式

public class BaseDao {

String DBUser = "root"; // 用户名
String DBPwd = "root";// 密码
String DBHost = "localhost"; // 服务器地址
String DBName = "myschool";// 数据库名称
int Port = 3306; // 端口号
int DBType = 1;    // 1mysql,2sqlserver,3orcale

Connection conn;          // 连接对象
PreparedStatement ps;     // 查询对象
ResultSet rs;             // 结果集

/**
* 打开连接
*/
public void open() {

try {
if (DBType == 1) {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://" + DBHost
+ ":" + Port + "/" + DBName, DBUser, DBPwd);

}

else if (DBType == 2) {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
conn = DriverManager
.getConnection("jdbc:sqlserver://" + DBHost + ":"
+ Port + ";databasename=" + DBName, DBUser,
DBPwd);

} else if (DBType == 3) {

// 编写orcala

Class.forName("Oracle.jdbc.driver.OracleDriver");
conn = DriverManager
.getConnection("jdbc:oracle:thin:@" + DBHost + ":"
+ Port + ":" + DBName, DBUser,
DBPwd);

}

} catch (Exception e) {
// TODO: handle exception
}

}
/**
*   关闭连接
*/
public void close() {

try {

if (rs != null)
rs.close(); // 如果结果集存在，就关闭结果集
ps.close(); // 关闭查询对象
conn.close(); // 关闭连接查询

} catch (Exception e) {
// TODO: handle exception
}

}

/**
* 执行 增删
* @param sql
* @param parm
* @return   a 为受影响的行数
*/
public int exectueUpdate(String sql, Object[] parm) {
open();
int a = 0;
try {

ps = conn.prepareStatement(sql);
if (parm != null) {

for (int i = 0; i < parm.length; i++) {
ps.setObject(i + 1, parm[i]);

}

}
a = ps.executeUpdate(); // 执行

} catch (Exception e) {
// TODO: handle exception
}

close();

return a;

}

/**
*   执行查询
* @param sql
* @param parm
* @return
*/

public ResultSet exectueQuery(String sql,Object[] parm){
open();
try {

ps = conn.prepareStatement(sql);
if (parm != null) {

for (int i = 0; i < parm.length; i++) {
ps.setObject(i + 1, parm[i]);

}

}
rs=ps.executeQuery();

} catch (Exception e) {
// TODO: handle exception
}

return rs;

}

}

          使用继承或者new也可以

package com.xing.myschool.dao;

import java.sql.SQLException;
import java.util.ArrayList;

import com.xing.myschool.entity.Student;

public class StudentDao extends BaseDao {

public int add(Student stu) {

String sql = "insert into student values(?,?,?,?)";
Object[] parm = { stu.getStudentid(), stu.getStudentName(),
stu.getStudentSex(), stu.getStudentAge() };

int a = exectueUpdate(sql, parm);

return a;

}

public int delete(int studentId) {
String sql = "delete from student where  Id=? ";
Object[] parm = { studentId };
int a = exectueUpdate(sql, parm);

return a;

}

public int update(Student stu) {

String sql = "update Student set name=?, age=?,sex=? where Id=?;";
Object[] parm = { stu.getStudentName(), stu.getStudentAge(),
stu.getStudentSex(), stu.getStudentid() };
int a = exectueUpdate(sql, parm);

return a;

}

public ArrayList<Student> getall() {

String sql = "select * from student";

ArrayList<Student> list = new ArrayList<Student>();
rs = exectueQuery(sql, null);

try {
while (rs.next()) {
Student stuu = new Student();
stuu.setStudentid(rs.getInt("id"));
stuu.setStudentName(rs.getString("name"));
stuu.setStudentSex(rs.getString("sex"));
stuu.setStudentAge(rs.getInt("age"));

list.add(stuu);

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

return list;

}

}

     所有的代码地址：点击打开链接

    使用的软件为：MyEclipse