From aca2aa4c7bd74acb8812cff1c6085dc891b754df Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E2=80=9C=E8=82=96=E9=92=9F=E5=87=AF=E9=9F=A9=E2=80=9D?= <“3175644391@qq.com”> Date: Wed, 17 May 2023 22:31:29 +0800 Subject: [PATCH 1/3] =?UTF-8?q?=E7=AC=AC=E4=B8=80=E6=AC=A1=E4=BD=9C?= =?UTF-8?q?=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../JDBC\344\275\234\344\270\232.md" | 215 ++++++++++++++++++ 1 file changed, 215 insertions(+) create mode 100644 "22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" diff --git "a/22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" "b/22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" new file mode 100644 index 0000000..00dc270 --- /dev/null +++ "b/22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" @@ -0,0 +1,215 @@ +### JDBC作业： + +1. MySQL中创建一个数据库student_db + +2. 库中创建student表 + +3. 表中数据如下 + +4. | 编号 | 姓名 | 性别 | + | ---- | ---- | ---- | + | 1 | 张三 | 男 | + | 2 | 李四 | 女 | + | 3 | 王五 | 男 | + +5. 编写java 4个类，分别实现以下功能 + + 1. 查询功能，查询student中所有数据 + + 2. 添加功能 + + 3. 修改功能 + + 4. 删除功能 + + ~~~ sql + create database student_db charset utf8; + use student_db; + create table student( + id int, + name varchar(20), + sex varchar(5) + ); + alter table student charset utf8; + insert into student values + (1,"张三","男"), + (2,"李四","女"), + (3,"王五","男"); + ~~~ + + + + ~~~ java + // 查询测试类 + import java.sql.*; + import java.util.concurrent.Callable; + + public class Test { + public static void main(String[] args) { + Connection conn = null; + Statement smt = null; + ResultSet rst = null; + // 1.建立驱动 + try { + Class.forName("com.mysql.jdbc.Driver"); + // 2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String uesrname = "root"; + String password = "root"; + conn = DriverManager.getConnection(url, uesrname, password); + // 3.定义sql语言 + String sql = "select * from student"; + // 4.获取执行SQL的对象 + smt = conn.createStatement(); + // 5.执行SQL + rst = smt.executeQuery(sql); + // 6.处理返回结果 + while(rst.next()){ + int id = rst.getInt("id"); + String name = rst.getString("name"); + String sex = rst.getString("sex"); + System.out.println(id+":"+name+"-"+sex); + } + } catch (ClassNotFoundException e) { + System.out.println("编译出错"); + } catch (SQLException e) { + System.out.println("SQL出错"); + } + // 7.释放资源 + try { + if (conn!=null){ + conn.close(); + } + if (smt!=null){ + smt.close(); + } + if (rst!=null){ + rst.close(); + } + } catch (SQLException e) { + System.out.println("释放资源出错"); + } + } + } + + ~~~ + + ~~~ java + // 添加测试类 + import java.sql.*; + + public class Insert { + public static void main(String[] args) { + // 1.建立驱动 + try { + Class.forName("com.mysql.jdbc.Driver"); + // 2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String uesrname = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url, uesrname, password); + // 3.定义sql语言 + String sql = "insert into student values (4,'赵六','女')"; + // 4.获取执行SQL的对象 + Statement smt = conn.createStatement(); + // 5.执行SQL + int i = smt.executeUpdate(sql); + // 6.处理返回结果 + if (i>0){ + System.out.println("添加成功"); + }else{ + System.out.println("添加失败"); + } + } catch (ClassNotFoundException e) { + System.out.println("编译出错"); + } catch (SQLException e) { + System.out.println("SQL出错"); + } + } + } + + ~~~ + + ~~~ java + // 删除测试类 + import java.sql.Connection; + import java.sql.DriverManager; + import java.sql.SQLException; + import java.sql.Statement; + + public class Delete { + public static void main(String[] args) { + // 1.建立驱动 + try { + Class.forName("com.mysql.jdbc.Driver"); + // 2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String uesrname = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url, uesrname, password); + // 3.定义sql语言 + String sql = "delete from student where id=4"; + // 4.获取执行SQL的对象 + Statement smt = conn.createStatement(); + // 5.执行SQL + int i = smt.executeUpdate(sql); + // 6.处理返回结果 + if (i>0){ + System.out.println("删除成功"); + }else{ + System.out.println("删除失败"); + } + } catch (ClassNotFoundException e) { + System.out.println("编译出错"); + } catch (SQLException e) { + System.out.println("SQL出错"); + } + } + } + + ~~~ + + ~~~ java + // 修改测试类 + import java.sql.Connection; + import java.sql.DriverManager; + import java.sql.SQLException; + import java.sql.Statement; + + public class Update { + public static void main(String[] args) { + try { + Class.forName("com.mysql.jdbc.Driver"); + // 2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String uesrname = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url, uesrname, password); + // 3.定义sql语言 + String sql = "update student set sex='女' where id=3"; + // 4.获取执行SQL的对象 + Statement smt = conn.createStatement(); + // 5.执行SQL + int i = smt.executeUpdate(sql); + // 6.处理返回结果 + if (i>0){ + System.out.println("修改成功"); + }else{ + System.out.println("修改失败"); + } + } catch (ClassNotFoundException e) { + System.out.println("编译出错"); + } catch (SQLException e) { + System.out.println("SQL出错"); + } + } + } + + ~~~ + + + +6. 扩展题【预习题】 + + 1. 能否实现一个类中，用四个方法来实现上面4个类的功能 + 2. 能否实现将查询的结果，封装成java对象 \ No newline at end of file -- Gitee From eaa1d2d6f0f475612aa120ba2df40400f50c93d0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E2=80=9C=E8=82=96=E9=92=9F=E5=87=AF=E9=9F=A9=E2=80=9D?= <“3175644391@qq.com”> Date: Wed, 17 May 2023 22:33:27 +0800 Subject: [PATCH 2/3] =?UTF-8?q?=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../20230517 JDBS\344\275\234\344\270\232.md" | 0 1 file changed, 0 insertions(+), 0 deletions(-) rename "22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" => "22 \350\202\226\351\222\237\345\207\257\351\237\251/20230517 JDBS\344\275\234\344\270\232.md" (100%) diff --git "a/22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" "b/22 \350\202\226\351\222\237\345\207\257\351\237\251/20230517 JDBS\344\275\234\344\270\232.md" similarity index 100% rename from "22 \350\202\226\351\222\237\345\207\257\351\237\251/JDBC\344\275\234\344\270\232.md" rename to "22 \350\202\226\351\222\237\345\207\257\351\237\251/20230517 JDBS\344\275\234\344\270\232.md" -- Gitee From 70ff91afbca2b2eeaa0b9edb2ba332b4bce33203 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E2=80=9C=E8=82=96=E9=92=9F=E5=87=AF=E9=9F=A9=E2=80=9D?= <“3175644391@qq.com”> Date: Mon, 22 May 2023 23:32:12 +0800 Subject: [PATCH 3/3] =?UTF-8?q?=E7=AC=AC=E4=BA=8C=E6=AC=A1=E4=BD=9C?= =?UTF-8?q?=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...06\345\220\210\344\275\234\344\270\232.md" | 199 ++++++++++++++++++ 1 file changed, 199 insertions(+) create mode 100644 "22 \350\202\226\351\222\237\345\207\257\351\237\251/20230522 JDBS\351\233\206\345\220\210\344\275\234\344\270\232.md" diff --git "a/22 \350\202\226\351\222\237\345\207\257\351\237\251/20230522 JDBS\351\233\206\345\220\210\344\275\234\344\270\232.md" "b/22 \350\202\226\351\222\237\345\207\257\351\237\251/20230522 JDBS\351\233\206\345\220\210\344\275\234\344\270\232.md" new file mode 100644 index 0000000..9b753a4 --- /dev/null +++ "b/22 \350\202\226\351\222\237\345\207\257\351\237\251/20230522 JDBS\351\233\206\345\220\210\344\275\234\344\270\232.md" @@ -0,0 +1,199 @@ +~~~ java +// 子类 +public class student { + private String id; + private String name; + private String sex; + + public student() { + } + + public student(String id, String name, String sex) { + this.id = id; + this.name = name; + this.sex = sex; + } + + public String getId() { + return id; + } + + public void setId(String id) { + this.id = id; + } + + public String getName() { + return name; + } + + public void setName(String name) { + this.name = name; + } + + public String getSex() { + return sex; + } + + public void setSex(String sex) { + this.sex = sex; + } + + @Override + public String toString() { + return "Test.student{" + + "id='" + id + '\'' + + ", name='" + name + '\'' + + ", sex='" + sex + '\'' + + '}'; + } +} + +~~~ + +~~~ java +// 包装类 +import java.sql.*; + +public class DBUtli { + private static final String url = "jdbc:mysql:///student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + private static final String username = "root"; + private static final String password = "root"; + + static{ + try { + Class.forName("com.mysql.jdbc.Driver"); + } catch (ClassNotFoundException e) { + System.out.println("驱动异常"); + e.printStackTrace(); + } + } + public static Connection getconn(){ + Connection conn = null; + try { + conn = DriverManager.getConnection(url, username, password); + } catch (SQLException e) { + System.out.println("SQL数据异常"); + e.printStackTrace(); + } + return conn; + } + public static ResultSet query(String sql, String ...keys){ + ResultSet rst = null; + try { + Connection conn = getconn(); + PreparedStatement pst = conn.prepareStatement(sql); + for (int i = 0; i < keys.length; i++) { + pst.setString((i+1),keys[i]); + } + rst = pst.executeQuery(sql); + } catch (SQLException e) { + System.out.println("获取对象失败"); + e.printStackTrace(); + } + return rst; + } +} + +~~~ + +~~~ java +// 查询测试类 +import java.sql.ResultSet; +import java.sql.SQLException; +import java.util.ArrayList; + +public class Test { + public static void main(String[] args) { + ArrayList list = new ArrayList<>(); + try { + String sql = "select * from student"; + ResultSet rst = DBUtli.query(sql); + while(rst.next()){ + int id = rst.getInt(1); + String name = rst.getString(2); + String sex = rst.getString(3); + System.out.println("编码:"+id+",姓名:"+name+",性别:"+sex); + } + } catch (SQLException e) { + System.out.println("SQL语句错误"); + } + for (int i = 0; i list = new ArrayList<>(); + String sql = "delete from student where name='张三'"; + int rst = DubTil.query(sql); + try { + System.out.println("修改成功"); + } catch (Exception e) { + e.printStackTrace(); + } + for (int i = 0; i