jdbc代码

package gz.itcast.util;

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工具类
* @author APPle
*
*/
public class JdbcUtil {
private static String url = null;
private static String user = null;
private static String password = null;
private static String driverClass = null;

/**
* 静态代码块中（只加载一次）
*/
static{
try {
//读取db.properties文件
Properties props = new Properties();
/**
*  . 代表java命令运行的目录
*  在java项目下，. java命令的运行目录从项目的根目录开始
*  在web项目下，  . java命令的而运行目录从tomcat/bin目录开始
*  所以不能使用点.
*/
//FileInputStream in = new FileInputStream("./src/db.properties");

/**
* 使用类路径的读取方式
*  / : 斜杠表示classpath的根目录
*     在java项目下，classpath的根目录从bin目录开始
*     在web项目下，classpath的根目录从WEB-INF/classes目录开始
*/
InputStream in = JdbcUtil.class.getResourceAsStream("/db.properties");

//加载文件
props.load(in);
//读取信息
url = props.getProperty("url");
user = props.getProperty("user");
password = props.getProperty("password");
driverClass = props.getProperty("driverClass");

//注册驱动程序
Class.forName(driverClass);
} catch (Exception e) {
e.printStackTrace();
System.out.println("驱程程序注册出错");
}
}

/**
* 抽取获取连接对象的方法
*/
public static Connection getConnection(){
try {
Connection conn = DriverManager.getConnection(url, user, password);
return conn;
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}

/**
* 释放资源的方法
*/
public static void close(Connection conn,Statement stmt){
if(stmt!=null){
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}

public static void close(Connection conn,Statement stmt,ResultSet rs){
if(rs!=null)
try {
rs.close();
} catch (SQLException e1) {
e1.printStackTrace();
throw new RuntimeException(e1);
}
if(stmt!=null){
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}
}

package gz.itcast.util;

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工具类
* @author APPle
*
*/
public class JdbcUtil {
private static String url = null;
private static String user = null;
private static String password = null;
private static String driverClass = null;

/**
* 静态代码块中（只加载一次）
*/
static{
try {
//读取db.properties文件
Properties props = new Properties();
/**
*  . 代表java命令运行的目录
*  在java项目下，. java命令的运行目录从项目的根目录开始
*  在web项目下，  . java命令的而运行目录从tomcat/bin目录开始
*  所以不能使用点.
*/
//FileInputStream in = new FileInputStream("./src/db.properties");

/**
* 使用类路径的读取方式
*  / : 斜杠表示classpath的根目录
*     在java项目下，classpath的根目录从bin目录开始
*     在web项目下，classpath的根目录从WEB-INF/classes目录开始
*/
InputStream in = JdbcUtil.class.getResourceAsStream("/db.properties");

//加载文件
props.load(in);
//读取信息
url = props.getProperty("url");
user = props.getProperty("user");
password = props.getProperty("password");
driverClass = props.getProperty("driverClass");

//注册驱动程序
Class.forName(driverClass);
} catch (Exception e) {
e.printStackTrace();
System.out.println("驱程程序注册出错");
}
}

/**
* 抽取获取连接对象的方法
*/
public static Connection getConnection(){
try {
Connection conn = DriverManager.getConnection(url, user, password);
return conn;
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}

/**
* 释放资源的方法
*/
public static void close(Connection conn,Statement stmt){
if(stmt!=null){
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}

public static void close(Connection conn,Statement stmt,ResultSet rs){
if(rs!=null)
try {
rs.close();
} catch (SQLException e1) {
e1.printStackTrace();
throw new RuntimeException(e1);
}
if(stmt!=null){
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}
}

package gz.itcast.b_statement;

import gz.itcast.util.JdbcUtil;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

import org.junit.Test;

/**
* 使用Statement执行DML语句
* @author APPle
*
*/
public class Demo2 {
private String url = "jdbc:mysql://localhost:3306/day17";
private String user = "root";
private String password = "root";

/**
* 增加
*/
@Test
public void testInsert(){
Connection conn = null;
Statement stmt = null;
try {
//通过工具类获取连接对象
conn = JdbcUtil.getConnection();

//3.创建Statement对象
stmt = conn.createStatement();

//4.sql语句
String sql = "INSERT INTO student(NAME,gender) VALUES('李四','女')";

//5.执行sql
int count = stmt.executeUpdate(sql);

System.out.println("影响了"+count+"行");

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally{
//关闭资源
/*if(stmt!=null)
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
if(conn!=null)
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}*/
JdbcUtil.close(conn, stmt);
}
}

/**
* 修改
*/
@Test
public void testUpdate(){
Connection conn = null;
Statement stmt = null;
//模拟用户输入
String name = "陈六";
int id = 3;
try {
/*//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");

//2.获取连接对象
conn = DriverManager.getConnection(url, user, password);*/
//通过工具类获取连接对象
conn = JdbcUtil.getConnection();

//3.创建Statement对象
stmt = conn.createStatement();

//4.sql语句
String sql = "UPDATE student SET NAME='"+name+"' WHERE id="+id+"";

System.out.println(sql);

//5.执行sql
int count = stmt.executeUpdate(sql);

System.out.println("影响了"+count+"行");

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally{
//关闭资源
/*if(stmt!=null)
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
if(conn!=null)
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}*/
JdbcUtil.close(conn, stmt);
}
}

/**
* 删除
*/
@Test
public void testDelete(){
Connection conn = null;
Statement stmt = null;
//模拟用户输入
int id = 3;
try {
/*//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");

//2.获取连接对象
conn = DriverManager.getConnection(url, user, password);*/
//通过工具类获取连接对象
conn = JdbcUtil.getConnection();

//3.创建Statement对象
stmt = conn.createStatement();

//4.sql语句
String sql = "DELETE FROM student WHERE id="+id+"";

System.out.println(sql);

//5.执行sql
int count = stmt.executeUpdate(sql);

System.out.println("影响了"+count+"行");

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally{
//关闭资源
/*if(stmt!=null)
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
if(conn!=null)
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(e);
}*/
JdbcUtil.close(conn, stmt);
}
}
}

package gz.itcast.b_statement;

import gz.itcast.util.JdbcUtil;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;

import org.junit.Test;

/**
* 使用Statement执行DQL语句（查询操作）
* @author APPle
*
*/
public class Demo3 {

@Test
public void test1(){
Connection conn = null;
Statement stmt = null;
try{
//获取连接
conn = JdbcUtil.getConnection();
//创建Statement
stmt = conn.createStatement();
//准备sql
String sql = "SELECT * FROM student";
//执行sql
ResultSet rs = stmt.executeQuery(sql);

//移动光标
/*boolean flag = rs.next();

flag = rs.next();
flag = rs.next();
if(flag){
//取出列值
//索引
int id = rs.getInt(1);
String name = rs.getString(2);
String gender = rs.getString(3);
System.out.println(id+","+name+","+gender);

//列名称
int id = rs.getInt("id");
String name = rs.getString("name");
String gender = rs.getString("gender");
System.out.println(id+","+name+","+gender);
}*/

//遍历结果
while(rs.next()){
int id = rs.getInt("id");
String name = rs.getString("name");
String gender = rs.getString("gender");
System.out.println(id+","+name+","+gender);
}

}catch(Exception e){
e.printStackTrace();
throw new RuntimeException(e);
}finally{
JdbcUtil.close(conn, stmt);
}
}
}

package gz.itcast.c_prepared;

import gz.itcast.util.JdbcUtil;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import org.junit.Test;
/**
* PreparedStatement執行sql語句
* @author APPle
*
*/
public class Demo1 {

/**
* 增加
*/
@Test
public void testInsert() {
Connection conn = null;
PreparedStatement stmt = null;
try {
//1.获取连接
conn = JdbcUtil.getConnection();

//2.准备预编译的sql
String sql = "INSERT INTO student(NAME,gender) VALUES(?,?)"; //?表示一个参数的占位符

//3.执行预编译sql语句(检查语法)
stmt = conn.prepareStatement(sql);

//4.设置参数值
/**
* 参数一： 参数位置  从1开始
*/
stmt.setString(1, "李四");
stmt.setString(2, "男");

//5.发送参数，执行sql
int count = stmt.executeUpdate();

System.out.println("影响了"+count+"行");

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt);
}
}

/**
* 修改
*/
@Test
public void testUpdate() {
Connection conn = null;
PreparedStatement stmt = null;
try {
//1.获取连接
conn = JdbcUtil.getConnection();

//2.准备预编译的sql
String sql = "UPDATE student SET NAME=? WHERE id=?"; //?表示一个参数的占位符

//3.执行预编译sql语句(检查语法)
stmt = conn.prepareStatement(sql);

//4.设置参数值
/**
* 参数一： 参数位置  从1开始
*/
stmt.setString(1, "王五");
stmt.setInt(2, 9);

//5.发送参数，执行sql
int count = stmt.executeUpdate();

System.out.println("影响了"+count+"行");

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt);
}
}

/**
* 删除
*/
@Test
public void testDelete() {
Connection conn = null;
PreparedStatement stmt = null;
try {
//1.获取连接
conn = JdbcUtil.getConnection();

//2.准备预编译的sql
String sql = "DELETE FROM student WHERE id=?"; //?表示一个参数的占位符

//3.执行预编译sql语句(检查语法)
stmt = conn.prepareStatement(sql);

//4.设置参数值
/**
* 参数一： 参数位置  从1开始
*/
stmt.setInt(1, 9);

//5.发送参数，执行sql
int count = stmt.executeUpdate();

System.out.println("影响了"+count+"行");

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt);
}
}

/**
* 查询
*/
@Test
public void testQuery() {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
//1.获取连接
conn = JdbcUtil.getConnection();

//2.准备预编译的sql
String sql = "SELECT * FROM student";

//3.预编译
stmt = conn.prepareStatement(sql);

//4.执行sql
rs = stmt.executeQuery();

//5.遍历rs
while(rs.next()){
int id = rs.getInt("id");
String name = rs.getString("name");
String gender = rs.getString("gender");
System.out.println(id+","+name+","+gender);
}

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
//关闭资源
JdbcUtil.close(conn,stmt,rs);
}
}
}

package gz.itcast.c_prepared;

import gz.itcast.util.JdbcUtil;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

import org.junit.Test;

/**
* 模拟用户登录效果
* @author APPle
*
*/
public class Demo2 {
//模拟用户输入
//private String name = "ericdfdfdfddfd' OR 1=1 -- ";
private String name = "eric";
//private String password = "123456dfdfddfdf";
private String password = "123456";

/**
* Statment存在sql被注入的风险
*/
@Test
public void testByStatement(){
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
//获取连接
conn = JdbcUtil.getConnection();

//创建Statment
stmt = conn.createStatement();

//准备sql
String sql = "SELECT * FROM users WHERE NAME='"+name+"' AND PASSWORD='"+password+"'";

//执行sql
rs = stmt.executeQuery(sql);

if(rs.next()){
//登录成功
System.out.println("登录成功");
}else{
System.out.println("登录失败");
}

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt ,rs);
}

}

/**
* PreparedStatement可以有效地防止sql被注入
*/
@Test
public void testByPreparedStatement(){
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
//获取连接
conn = JdbcUtil.getConnection();

String sql = "SELECT * FROM users WHERE NAME=? AND PASSWORD=?";

//预编译
stmt = conn.prepareStatement(sql);

//设置参数
stmt.setString(1, name);
stmt.setString(2, password);

//执行sql
rs = stmt.executeQuery();

if(rs.next()){
//登录成功
System.out.println("登录成功");
}else{
System.out.println("登录失败");
}

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt ,rs);
}

}
}

package gz.itcast.d_callable;

import gz.itcast.util.JdbcUtil;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.ResultSet;

import org.junit.Test;

/**
* 使用CablleStatement调用存储过程
* @author APPle
*
*/
public class Demo1 {

/**
* 调用带有输入参数的存储过程
* CALL pro_findById(4);
*/
@Test
public void test1(){
Connection conn = null;
CallableStatement stmt = null;
ResultSet rs = null;
try {
//获取连接
conn = JdbcUtil.getConnection();

//准备sql
String sql = "CALL pro_findById(?)"; //可以执行预编译的sql

//预编译
stmt = conn.prepareCall(sql);

//设置输入参数
stmt.setInt(1, 6);

//发送参数
rs = stmt.executeQuery(); //注意： 所有调用存储过程的sql语句都是使用executeQuery方法执行！！！

//遍历结果
while(rs.next()){
int id = rs.getInt("id");
String name = rs.getString("name");
String gender = rs.getString("gender");
System.out.println(id+","+name+","+gender);
}

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt ,rs);
}
}

/**
* 执行带有输出参数的存储过程
* CALL pro_findById2(5,@NAME);
*/
@Test
public void test2(){
Connection conn = null;
CallableStatement stmt = null;
ResultSet rs = null;
try {
//获取连接
conn = JdbcUtil.getConnection();
//准备sql
String sql = "CALL pro_findById2(?,?)"; //第一个？是输入参数，第二个？是输出参数

//预编译
stmt = conn.prepareCall(sql);

//设置输入参数
stmt.setInt(1, 6);
//设置输出参数(注册输出参数)
/**
* 参数一： 参数位置
* 参数二： 存储过程中的输出参数的jdbc类型    VARCHAR(20)
*/
stmt.registerOutParameter(2, java.sql.Types.VARCHAR);

//发送参数，执行
stmt.executeQuery(); //结果不是返回到结果集中，而是返回到输出参数中

//得到输出参数的值
/**
* 索引值： 预编译sql中的输出参数的位置
*/
String result = stmt.getString(2); //getXX方法专门用于获取存储过程中的输出参数

System.out.println(result);

} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
} finally {
JdbcUtil.close(conn, stmt ,rs);
}
}
}