JDBC连接Oracle数据库，实现增删改查，简单封装jdbc
JDBC
- JDBC是一套标准(接口)，用来连接【关系型数据库】。各个数据库厂商去实现具体的功能，用户使用时使用相同一套标准即可。但是在使用时得导入不同公司提供的包(里面包含了具体实现)。
- 连接数据库的方式，常见有两种: ODBC和JDBC，分属两个不同的阵营。其中JDBC是java版本的ODBC.
- ODBC(Open Database Connectivity)开放的数据库连接，由微软开发出来。是一套公共的接口(标准)，用来连接数据库。
连接数据库5(6)大步骤
在阐明步骤之前要先说JDBC的4要素
1).String driver = “jar包Driver类全包名”;
告诉我们具体数据库驱动在哪里，方便后期注册。
String dirver = “oracle.jdbc.driver.OracleDriver”;
2).URL 确定连接到那个具体的数据库
jdbc:oracle:oci:@< SID > oci连接方式
jdbc:oracle:thin:@< SID > thin连接方式
String url = “jdbc:oracle:thin:@127.0.0.1:1521:XE”;
3).String user = “用户名”;
4).String password = “密码”;
- 注册驱动（3种方法）
a.使用类加载器
String driverName = “oracle.jdbc.driver.OracleDriver”;
Class.forName(driverName);
b.实例化一个驱动对象
实例化驱动对象
Driver driver = new oracle.jdbc.driver.OracleDriver();
注册驱动
DriverManager.registerDriver(driver);
c.使用property
System.setProperty(“jdbc.drivers”, “oracle.jdbc.driver.OracleDriver”);
使用【系统配置】进行驱动注册，其中【第一个参数值固定】，第二个参数为驱动类的全包名。
Class.forName(oracle.jdbc.driver.OracleDriver);
-
建立连接(2种方式)
第一种是利用DriverManager.getConnection(url, user, passwd);
第二种是利用Driver类直接连接(其实第一种底层也是通过Driver建立的连接)。
Driver driver = new oracle.jdbc.driver.OracDriver();
Properties info = new Properties();
info.setProperty(“user”,"");
info.setProperty(“password”,"");
conn = driver.connect(url,info);关于DriverManager和Driver的关系
一个DriverManager可以管理多个Driver，在具体进行数据库连接时，管理类借助Driver里面的connect方法建立连接。
conn = DriverManager.getConnection(jdbc:oracle:thin:@127.0.01:1521:XE, oracle, oracle);
- 创建Statement对象或PrepareStatement对象
stmt = conn.createStatement();
注意：要执行的sql语句可以分为同构和异构
异构 结构不同的语句。Statement语句执行，每次执行sql语句，都会把sql语句通过网络发送到服务器，然后让服务器实现功能。
Statement stmt = conn.createStatement();
String sql = "select * from s_emp";
stmt.execute(sql);
stmt.executeQuery(sql);
stmt.executeUpdate(sql);
一共有三种执行方式，他们都可以正常执行select insert update delete语句，区别在于返回值类型。
execute(sql)返回boolean，执行【返回结果集则true】,否则false;
executeUpdate(sql)【返回int】,执行影响了多少条数据;
executeQuery(sql)返回结果集ResultSet。
同构 结构相同的sql语句。PrepareStatement预编译同构sql语句,在实际使用时，可以提前将Sql语句发送给数据库进行【预编译】，然后每次只需要传输值即可，这样子可以提高效率。如：
String sql = "insert into student(id,name,age,birthday) values(?,?,?,?)";
PrepareStatement ps = conn.prepareStatement(sql);
ps.setInt(1,7);
ps.setString(2, "王五");
ps.setInt(3, 21);
- 执行sql语句
String sql = "select * from student";
- 如果是sql语句是Select语句的话，操作查询返回的结果集
这一步骤针对sql语句是select语句时，才会有查询结果返回。将查询回来的学生信息封装成一个学生对象，放入list集合中。
List list = new ArrayList<>();
Student s = null;
while(rs.next()){
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
s = new Student(id, name, age);
list.add(s);
}
- 关闭连接通道
if(stmt!=null)
stmt.close();
if(conn!=null)
conn.close();
Statement增删改查
package com.briup.jdbcday1;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import org.junit.Test;
public class StatementTest {
private static String driver = "oracle.jdbc.driver.OracleDriver";
private static String url = "jdbc:oracle:thin:@127.0.01:1521:XE";
private static String user = "oracle";
private static String password = "oracle";
@Test
public void test_insert(){
Connection conn = null;
Statement stmt = null;
try {
//1.注册驱动
Class.forName(driver);
//2.建立连接
conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);
//3.创建Statement
stmt = conn.createStatement();
//4.执行sql
Student s = new Student(4, "tom4", 18);
String sql = "insert into student values("+s.getId()+",'"+s.getName()+"',"+s.getAge()+")";
// stmt.execute(sql);//boolean
// stmt.executeQuery(sql);//ResultSet//select
// stmt.executeUpdate(sql);//int
stmt.execute(sql);
//5.操作结果集（如果有）
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
//6.关闭资源
try {
if(stmt!=null)stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(conn!=null)conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Test
public void test_update(){
Connection conn = null;
Statement stmt = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);
stmt = conn.createStatement();
String sql = "update student set name='zs' where id= 1";
stmt.execute(sql);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
if(stmt!=null)stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(conn!=null)conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Test
public void test_delete(){
Connection conn = null;
Statement stmt = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);
stmt = conn.createStatement();
String sql = "delete from student where id = 1";
stmt.execute(sql);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
if(stmt!=null)stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(conn!=null)conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Test
public void test_select(){
Connection conn = null;
Statement stmt = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);
stmt = conn.createStatement();
String sql = "select * from student";
ResultSet rs = stmt.executeQuery(sql);
//5.操作结果集
List list = new ArrayList<>();
Student s = null;
while(rs.next()){
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
s = new Student(id, name, age);
list.add(s);
}
for(Student stu : list){
System.out.println(stu);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
if(stmt!=null)stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(conn!=null)conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
PreparedStatement新增的两种方式
package com.briup.jdbcday1;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import org.junit.Test;
public class PreparedStatementTest {
private static String driver = "oracle.jdbc.driver.OracleDriver";
private static String url = "jdbc:oracle:thin:@127.0.01:1521:XE";
private static String user = "oracle";
private static String password = "oracle";
@Test
public void test_insert(){
Connection conn = null;
PreparedStatement ps = null;
try {
//1.注册驱动
Class.forName(driver);
//2.建立连接
conn = DriverManager.getConnection(url, user, password);
//3.创建Statement
String sql = "insert into student values(?,?,?)";
ps = conn.prepareStatement(sql);
//4.执行sql
ps.setLong(1, 5L);
ps.setString(2, "tom5");
ps.setInt(3, 18);
ps.execute();//不能写成ps.execute(sql);
//5.操作结果集（如果有）
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
//6.关闭资源
try {
if(ps!=null)ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(conn!=null)conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//批量新 增
@Test
void test_insert2(){
Connection conn = null;
PreparedStatement ps = null;
try {
//1.注册驱动
Class.forName(driver);
//2.建立连接
conn = DriverManager.getConnection(url, user, password);
//设置手动提交事务
conn.setAutoCommit(false);
//3.创建Statement
String sql = "insert into student values(?,?,?)";
ps = conn.prepareStatement(sql);
//4.执行sql
for(int i=1;i<11;i++){
ps.setLong(1, i);
ps.setString(2, "tom"+i);
ps.setInt(3, 18);
ps.execute();//不能写成ps.execute(sql);
}
//5.操作结果集（如果有）
conn.commit();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
//6.关闭资源
try {
if(ps!=null)ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(conn!=null)conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
构建连接工厂
上面的写法需要写大量的重复代码，所以最好将这些步骤封装起来，4要素也放在配置文件中直接读取后使用.
配置文件：文件名db.properties
driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@127.0.0.1:1521:XE
user=oracle
password=oracle
连接工厂
package com.briup.jdbcday2;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class ConnectionFactory {
private static String driver;
private static String url;
private static String user;
private static String password;
static{
try {
Properties p=new Properties();
p.load(ConnectionFactory.class.getResourceAsStream("db.properties"));
driver=p.getProperty("driver");
url=p.getProperty("url");
user=p.getProperty("user");
password=p.getProperty("password");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static Connection getConnection() {
Connection conn = null;
try {
// 1.注册驱动
Class.forName(driver);
// 2.建立连接
conn = DriverManager.getConnection(url, user, password);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
public static void close(Connection conn, Statement stmt) {
close(null, conn, stmt);
}
public static void close(ResultSet rs, Connection conn, Statement stmt) {
try {
if (rs != null)
rs.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if (stmt != null)
stmt.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if (conn != null)
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
}
}
JDBC封装工具类
package com.briup.jdbcday2;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
public class JDBCUtil {
public static void execute_DML_stmt(String sql) {
Connection conn = null;
Statement stmt = null;
try {
conn = ConnectionFactory.getConnection();
stmt = conn.createStatement();
stmt.execute(sql);
ConnectionFactory.close(conn, stmt);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void execute_select_stmt(String sql,IWorkAdapter work) {
Connection conn = null;
Statement stmt = null;
try {
conn = ConnectionFactory.getConnection();
stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql);
//处理结果集
work.processRs(rs);
ConnectionFactory.close(conn, stmt);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void execute_DML_ps(String sql, IWorkAdapter work) {
Connection conn = null;
PreparedStatement ps = null;
try {
conn = ConnectionFactory.getConnection();
ps=conn.prepareStatement(sql);
work.setValues(ps);
ps.execute();
//ps.executeBatch();
ConnectionFactory.close(conn, ps);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void execute_select_ps(String sql, IWorkAdapter work) {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs=null;
try {
conn = ConnectionFactory.getConnection();
ps=conn.prepareStatement(sql);
work.setValues(ps);
rs = ps.executeQuery();
work.processRs(rs);
ConnectionFactory.close(conn, ps);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
两个接口，一个用于处理结果集，一个用于设置参数
package com.briup.jdbcday2;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public interface IWork {
public void processRs(ResultSet rs);
public void setValues(PreparedStatement ps);
}
package com.briup.jdbcday2;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public abstract class IWorkAdapter implements IWork{
@Override
public void processRs(ResultSet rs) {
// TODO Auto-generated method stub
}
@Override
public void setValues(PreparedStatement ps) {
// TODO Auto-generated method stub
}
}
使用封装JDBC对数据库进行增删改查
package com.briup.jdbcday2;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class JDBCWork2 {
public static void main(String[] args) {
Teacher teacher =new Teacher(10,"椿",8000);
List list=new ArrayList<>();
for(int i=0;i<500;i++){
list.add(new Teacher(i,"teacher"+i,25));
}
//teacherInsert(teacher);
//teacherUpdate(teacher);
//teacherDelete(teacher);
teacherSelect(teacher);
//teacherInsertBatch(list);
}
public static void teacherInsert(Teacher teacher){
String sqlI="insert into teacher1 values(?,?,?)";
JDBCUtil.execute_DML_ps(sqlI, new IWorkAdapter() {
@Override
public void setValues(PreparedStatement ps) {
try {
ps.setLong(1, teacher.getId());
ps.setString(2, teacher.getName());
ps.setInt(3, teacher.getAge());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
public static void teacherUpdate(Teacher teacher){
String sqlU="update teacher1 set name= ? where id = ?";
JDBCUtil.execute_DML_ps(sqlU, new IWorkAdapter() {
@Override
public void setValues(PreparedStatement ps) {
try {
ps.setString(1, "湫");
ps.setLong(2, teacher.getId());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
public static void teacherDelete(Teacher teacher){
String sqlD="delete from teacher1 where id =?";
JDBCUtil.execute_DML_ps(sqlD, new IWorkAdapter() {
@Override
public void setValues(PreparedStatement ps) {
try {
ps.setLong(1, teacher.getId());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
public static void teacherSelect(Teacher teacher){
String sqlS="select * from teacher1 where id=?";
JDBCUtil.execute_select_ps(sqlS, new IWorkAdapter() {
Teacher t = null;
@Override
public void setValues(PreparedStatement ps) {
try {
ps.setLong(1, teacher.getId());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void processRs(ResultSet rs) {
try {
while (rs.next()) {
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
t = new Teacher(id, name, age);
System.out.println(t);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
public static void teacherInsertBatch(List list){
String sqlI="insert into teacher1 values(?,?,?)";
JDBCUtil.execute_DML_ps(sqlI, new IWorkAdapter() {
@Override
public void setValues(PreparedStatement ps) {
try {
for(int i=0;i<500;i++){
ps.setLong(1, list.get(i).getId());
ps.setString(2, list.get(i).getName());
ps.setInt(3, list.get(i).getAge());
ps.addBatch();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}