1.jdbcutiul的代码，
1 package gz.itcast.util;
2
3 import java.io.InputStream;
4 import java.sql.Connection;
5 import java.sql.DriverManager;
6 import java.sql.ResultSet;
7 import java.sql.SQLException;
8 import java.sql.Statement;
9 import java.util.Properties;
10
11 /**
12 * jdbc工具类
13 * @author APPle
14 *
15 */
16 public class JdbcUtil {
17 private static String url = null;
18 private static String user = null;
19 private static String password = null;
20 private static String driverClass = null;
21
22 /**
23 * 静态代码块中（只加载一次）
24 */
25 static{
26 try {
27 //读取db.properties文件
28 Properties props = new Properties();
29 /**
30 * . 代表java命令运行的目录
31 * 在java项目下，. java命令的运行目录从项目的根目录开始
32 * 在web项目下， . java命令的而运行目录从tomcat/bin目录开始
33 * 所以不能使用点.
34 */
35 //FileInputStream in = new FileInputStream("./src/db.properties");
36
37 /**
38 * 使用类路径的读取方式
39 * / : 斜杠表示classpath的根目录
40 * 在java项目下，classpath的根目录从bin目录开始
41 * 在web项目下，classpath的根目录从WEB-INF/classes目录开始
42 */
43 InputStream in = JdbcUtil.class.getResourceAsStream("/db.properties");
44
45 //加载文件
46 props.load(in);
47 //读取信息
48 url = props.getProperty("url");
49 user = props.getProperty("user");
50 password = props.getProperty("password");
51 driverClass = props.getProperty("driverClass");
52
53
54 //注册驱动程序
55 Class.forName(driverClass);
56 } catch (Exception e) {
57 e.printStackTrace();
58 System.out.println("驱程程序注册出错");
59 }
60 }
61
62 /**
63 * 抽取获取连接对象的方法
64 */
65 public static Connection getConnection(){
66 try {
67 Connection conn = DriverManager.getConnection(url, user, password);
68 return conn;
69 } catch (SQLException e) {
70 e.printStackTrace();
71 throw new RuntimeException(e);
72 }
73 }
74
75
76 /**
77 * 释放资源的方法
78 */
79 public static void close(Connection conn,Statement stmt){
80 if(stmt!=null){
81 try {
82 stmt.close();
83 } catch (SQLException e) {
84 e.printStackTrace();
85 throw new RuntimeException(e);
86 }
87 }
88 if(conn!=null){
89 try {
90 conn.close();
91 } catch (SQLException e) {
92 e.printStackTrace();
93 throw new RuntimeException(e);
94 }
95 }
96 }
97
98 public static void close(Connection conn,Statement stmt,ResultSet rs){
99 if(rs!=null)
100 try {
101 rs.close();
102 } catch (SQLException e1) {
103 e1.printStackTrace();
104 throw new RuntimeException(e1);
105 }
106 if(stmt!=null){
107 try {
108 stmt.close();
109 } catch (SQLException e) {
110 e.printStackTrace();
111 throw new RuntimeException(e);
112 }
113 }
114 if(conn!=null){
115 try {
116 conn.close();
117 } catch (SQLException e) {
118 e.printStackTrace();
119 throw new RuntimeException(e);
120 }
121 }
122 }
123 }
2.静态sql查询
2.1建表
1 package gz.itcast.util;
2
3 import java.io.InputStream;
4 import java.sql.Connection;
5 import java.sql.DriverManager;
6 import java.sql.ResultSet;
7 import java.sql.SQLException;
8 import java.sql.Statement;
9 import java.util.Properties;
10
11 /**
12 * jdbc工具类
13 * @author APPle
14 *
15 */
16 public class JdbcUtil {
17 private static String url = null;
18 private static String user = null;
19 private static String password = null;
20 private static String driverClass = null;
21
22 /**
23 * 静态代码块中（只加载一次）
24 */
25 static{
26 try {
27 //读取db.properties文件
28 Properties props = new Properties();
29 /**
30 * . 代表java命令运行的目录
31 * 在java项目下，. java命令的运行目录从项目的根目录开始
32 * 在web项目下， . java命令的而运行目录从tomcat/bin目录开始
33 * 所以不能使用点.
34 */
35 //FileInputStream in = new FileInputStream("./src/db.properties");
36
37 /**
38 * 使用类路径的读取方式
39 * / : 斜杠表示classpath的根目录
40 * 在java项目下，classpath的根目录从bin目录开始
41 * 在web项目下，classpath的根目录从WEB-INF/classes目录开始
42 */
43 InputStream in = JdbcUtil.class.getResourceAsStream("/db.properties");
44
45 //加载文件
46 props.load(in);
47 //读取信息
48 url = props.getProperty("url");
49 user = props.getProperty("user");
50 password = props.getProperty("password");
51 driverClass = props.getProperty("driverClass");
52
53
54 //注册驱动程序
55 Class.forName(driverClass);
56 } catch (Exception e) {
57 e.printStackTrace();
58 System.out.println("驱程程序注册出错");
59 }
60 }
61
62 /**
63 * 抽取获取连接对象的方法
64 */
65 public static Connection getConnection(){
66 try {
67 Connection conn = DriverManager.getConnection(url, user, password);
68 return conn;
69 } catch (SQLException e) {
70 e.printStackTrace();
71 throw new RuntimeException(e);
72 }
73 }
74
75
76 /**
77 * 释放资源的方法
78 */
79 public static void close(Connection conn,Statement stmt){
80 if(stmt!=null){
81 try {
82 stmt.close();
83 } catch (SQLException e) {
84 e.printStackTrace();
85 throw new RuntimeException(e);
86 }
87 }
88 if(conn!=null){
89 try {
90 conn.close();
91 } catch (SQLException e) {
92 e.printStackTrace();
93 throw new RuntimeException(e);
94 }
95 }
96 }
97
98 public static void close(Connection conn,Statement stmt,ResultSet rs){
99 if(rs!=null)
100 try {
101 rs.close();
102 } catch (SQLException e1) {
103 e1.printStackTrace();
104 throw new RuntimeException(e1);
105 }
106 if(stmt!=null){
107 try {
108 stmt.close();
109 } catch (SQLException e) {
110 e.printStackTrace();
111 throw new RuntimeException(e);
112 }
113 }
114 if(conn!=null){
115 try {
116 conn.close();
117 } catch (SQLException e) {
118 e.printStackTrace();
119 throw new RuntimeException(e);
120 }
121 }
122 }
123 }
2.2插入数据
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);
}
}
}
2.3查询数据
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);
}
}
}
3.动态SQL查询
3.1更新
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);
}
}
}
3.2查询
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);
}
}
}
4.执行存储过程
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);
}
}
}
时间： 2024-11-10 01:01:48