From 9584d8544e608b53d180281160c568da71c46401 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E6=98=BE=E4=B9=89?= <3515252188@qq.com> Date: Thu, 5 Dec 2024 22:21:48 +0800 Subject: [PATCH] 123 --- .../20241205 java/src/main/java/Mdd.java" | 21 +++ .../src/main/java/utils/MysqlUtil.java" | 16 +++ .../20241205 java/src/test/java/Test01.java" | 128 ++++++++++++++++++ ...47\220\206java\351\241\271\347\233\256.md" | 114 ++++++++++++++++ 4 files changed, 279 insertions(+) create mode 100644 "\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/Mdd.java" create mode 100644 "\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/utils/MysqlUtil.java" create mode 100644 "\347\216\213\346\230\276\344\271\211/20241205 java/src/test/java/Test01.java" create mode 100644 "\347\216\213\346\230\276\344\271\211/20241205 java/\344\275\277\347\224\250maven\346\236\204\345\273\272\345\222\214\347\256\241\347\220\206java\351\241\271\347\233\256.md" diff --git "a/\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/Mdd.java" "b/\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/Mdd.java" new file mode 100644 index 0000000..c5cda53 --- /dev/null +++ "b/\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/Mdd.java" @@ -0,0 +1,21 @@ +import java.sql.*; + +public class Mdd { + public static void main(String[] args) throws ClassNotFoundException, SQLException { + Class.forName("com.mysql.cj.jdbc.Driver"); + String url ="jdbc:mysql:///test01"; + String user="root"; + String pwd = "123456"; + Connection con = DriverManager.getConnection(url, user, pwd); + String sql = "select * from student"; + PreparedStatement pr = con.prepareStatement(sql); + ResultSet re = pr.executeQuery(); + while (re.next()) { + int sId = re.getInt("s_id"); + String sName = re.getString("s_name"); + int sAge = re.getInt("s_age"); + String sSex = re.getString("s_sex"); + System.out.println(sId+"\t"+sName+"\t"+sAge+"\t"+sSex); + } + } +} diff --git "a/\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/utils/MysqlUtil.java" "b/\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/utils/MysqlUtil.java" new file mode 100644 index 0000000..9036da3 --- /dev/null +++ "b/\347\216\213\346\230\276\344\271\211/20241205 java/src/main/java/utils/MysqlUtil.java" @@ -0,0 +1,16 @@ +package utils; + +import java.sql.Connection; +import java.sql.DriverManager; +import java.sql.SQLException; + +public class MysqlUtil { + public static Connection GetCon () throws SQLException, ClassNotFoundException { + Class.forName("com.mysql.cj.jdbc.Driver"); + String url ="jdbc:mysql:///test01"; + String user="root"; + String pwd = "123456"; + Connection con = DriverManager.getConnection(url, user, pwd); + return con; + } +} diff --git "a/\347\216\213\346\230\276\344\271\211/20241205 java/src/test/java/Test01.java" "b/\347\216\213\346\230\276\344\271\211/20241205 java/src/test/java/Test01.java" new file mode 100644 index 0000000..c3a0ee4 --- /dev/null +++ "b/\347\216\213\346\230\276\344\271\211/20241205 java/src/test/java/Test01.java" @@ -0,0 +1,128 @@ +import org.junit.Test; +import utils.MysqlUtil; + +import java.sql.*; + +public class Test01 { + //查询 + @Test + public void T1select() throws ClassNotFoundException, SQLException { + Connection con = MysqlUtil.GetCon(); + String sql = "select * from student"; + PreparedStatement pr = con.prepareStatement(sql); + ResultSet re = pr.executeQuery(); + while (re.next()) { + int sId = re.getInt("s_id"); + String sName = re.getString("s_name"); + int sAge = re.getInt("s_age"); + String sSex = re.getString("s_sex"); + System.out.println(sId + "\t" + sName + "\t" + sAge + "\t" + sSex); + } + re.close(); + pr.close(); + con.close(); + } + + //添加 + @Test + public void T1add() throws ClassNotFoundException, SQLException { + Connection con = MysqlUtil.GetCon(); + String sql = "INSERT INTO test01.student ( s_name, s_age, s_sex) VALUES (123,456,789);"; + PreparedStatement pr = con.prepareStatement(sql); + int i = pr.executeUpdate(); + if (i > 0) { + System.out.println("添加成功"); + T1select(); + } else { + System.out.println("错误"); + } + pr.close(); + con.close(); + } + + //删除 + @Test + public void T1del() throws ClassNotFoundException, SQLException { + Connection con = MysqlUtil.GetCon(); + // 查询表中最后一条数据的 ID + String lastIdSql = "select Max(s_id) from student"; + PreparedStatement pr = con.prepareStatement(lastIdSql); + ResultSet re = pr.executeQuery(); + long lastId = -1; + if (re.next()) { + lastId = re.getInt("Max(s_id)"); + } + re.close(); + pr.close(); + if (lastId == -1) { + System.out.println("表中没有数据"); + con.close(); + return; + } + + //删除最后一条数据 + String deleSql = "delete from student where s_id = ?;"; + PreparedStatement pr1 = con.prepareStatement(deleSql); + pr1.setLong(1, lastId); + int i = pr1.executeUpdate(); + if (i > 0) { + System.out.println("删除最后一条数据，ID:" + lastId); + T1select(); + } else { + System.out.println("错误"); + } + pr1.close(); + con.close(); + } + + //修改 + @Test + public void T1Revise() throws ClassNotFoundException, SQLException { + Connection con = MysqlUtil.GetCon(); + // 查询表中第一条数据的 ID + String firstSql = "select Min(s_id) from student"; + PreparedStatement pr = con.prepareStatement(firstSql); + ResultSet re = pr.executeQuery(); + long firstId = -1; + if (re.next()) { + firstId = re.getInt("Min(s_id)"); + } + re.close(); + pr.close(); + if (firstId == -1) { + System.out.println("表中没有数据"); + con.close(); + return; + } + + //删除最后一条数据 + String updateSql = "update student set s_name =1,s_age=1,s_sex=1 where s_id=?"; + PreparedStatement pr1 = con.prepareStatement(updateSql); + pr1.setLong(1, firstId); + int i = pr1.executeUpdate(); + if (i > 0) { + System.out.println("修改第一条数据，ID:" + firstId); + T1select(); + } else { + System.out.println("错误"); + } + pr1.close(); + con.close(); + } + +} + + + + + + + + + + + + + + + diff --git "a/\347\216\213\346\230\276\344\271\211/20241205 java/\344\275\277\347\224\250maven\346\236\204\345\273\272\345\222\214\347\256\241\347\220\206java\351\241\271\347\233\256.md" "b/\347\216\213\346\230\276\344\271\211/20241205 java/\344\275\277\347\224\250maven\346\236\204\345\273\272\345\222\214\347\256\241\347\220\206java\351\241\271\347\233\256.md" new file mode 100644 index 0000000..7d54611 --- /dev/null +++ "b/\347\216\213\346\230\276\344\271\211/20241205 java/\344\275\277\347\224\250maven\346\236\204\345\273\272\345\222\214\347\256\241\347\220\206java\351\241\271\347\233\256.md" @@ -0,0 +1,114 @@ +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205153707.png) + +## 一、下载Maven并解压 + +### 1. Maven官网下载地址：[http://maven.apache.org/download.cgi](https://maven.apache.org/download.cgi "http://maven.apache.org/download.cgi") + +截止目前，Maven的最新版为` 3.9.9`，如无特殊需要，直接下载箭头处的最新版压缩包即可。 +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204232519.png) + +### 2. 下载后解压，将Maven的压缩包解压到你电脑某个目录 ，如C:\apache-maven-3.9.9 +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204232942.png) + + + +## 二、本地仓储配置 + +从中央仓库下载的jar包，都会统一存放到本地仓库中。我们需要配置本地仓库的位置。 + +### 1.新建一个文件夹，名称为“mvn-repository”，假设路径为：C:\apache-maven-3.9.9\mvn-repository +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204233218.png) +### 2.配置setting.xml文件 + +- 在Maven解压文件中打开**conf目录**下的**settings.xml文件** +- ![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204233311.png) +- 添加下面这行语句以配置本地仓储位置 +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204233546.png) + +--------- + + + +## 三、设置阿里云镜像 + +Maven默认访问国外服务器下载包，速度很慢。配置**_阿里云镜像_**下载包会比较快。 + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204233904.png) + +打开**conf目录**下的**settings.xml**文件， +```xml +<-- 在标签下添加标签：--> + + aliyunmaven + * + 阿里云公共仓库 + https://maven.aliyun.com/repository/public + +``` + +-------------- + +## 四，设置IDEA,启用MAVEN相关配置 + + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204234208.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204234312.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204234444.png) +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204234615.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204234547.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241204234655.png) + +## 五、设置pom.xml文件 ，配置想要的库的坐标。 +从maven仓库：[https://mvnrepository.com/](https://gitee.com/link?target=https%3A%2F%2Fmvnrepository.com%2F) 中搜索要的库的名称 ，复制 对应 的XML到pom.xml +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205000057.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205000123.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205000513.png) + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205000351.png) + + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205000539.png) +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205000605.png) + +## 六、测试 + +```java +import java.sql.*; + +public class Mdd { + + public static void main(String[] args) throws ClassNotFoundException, SQLException { + Class.forName("com.mysql.cj.jdbc.Driver"); + // 创建连接 + String url = "jdbc:mysql://localhost:3306/ok50?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String username = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url, username, password); + // 创建stmt对象 + Statement stmt = conn.createStatement(); + + String select = "select * from student"; + ResultSet rs = stmt.executeQuery(select); + // 返回结果 +// if (rs.next()) { + while (rs.next()) { + int stuId = rs.getInt("s_id"); + String name = rs.getString("s_name"); + String birth = rs.getString("s_birth"); + String sex = rs.getString("s_sex"); + System.out.println(stuId + "\t" + name + "\t" + sex+ "\t" + birth); + } + + } +} +``` + +![image.png](https://gitee.com/onesheet/images_backup/raw/master/images/20241205002215.png) + +## 七、用Maven重构大一的项目 \ No newline at end of file -- Gitee