JDBC之——Statement实现对数据库的增删改操作

拼搏现实的明天。 2022-05-19 00:37 364阅读 0赞

一、Statement接口引入

作用：用于执行静态SQL语句并返回它所生成结果的对象

int executeUpdate(String sql) 执行给定SQL语句，该语句可能为INSERT、UPDATE、或DELETE语句，或者不返回任何内容的SQL语句（如SQLDDL语句）。

void close() 立即释放此Statement对象的数据库和JDBC资源，而不是等待该对象自动关闭时发生此操作。

二、使用Statement接口实现添加数据操作

demo1:

  1. public class Demo1 {
  2.     public static void main(String[] args) throws Exception {
  3.         DbUtil dbUtil = new DbUtil();
  4.         String sql = "insert into t_book values(null,'java牛逼',888,'B哥',1)";
  5.         Connection con = dbUtil.getCon();//获取数据库连接
  6.         Statement stmt = con.createStatement();//获取Statement
  7.         int result = stmt.executeUpdate(sql);
  8.         System.out.println("操作的结果："+result+"数据");
  9.         stmt.close();//关闭statement
  10.         con.close();//关闭连接
  11.     }
  12. }

demo2:

  1. //工具类
  2. public class DbUtil {
  3.     //数据库地址
  4.     private static String dbUrl="jdbc:mysql://localhost:3306/db_book";
  5.     //用户名
  6.     private static String dbUserName="root";
  7.     //密码
  8.     private static String dbPassword="root";
  9.     //驱动名称
  10.     private static String jdbcName="com.mysql.jdbc.Driver";
  11.     /**
  12.      * 获取数据库连接
  13.      *     1.加载数据库驱动
  14.      *  2.获取数据库连接
  15.      */
  16.     public Connection getCon() throws Exception {
  17.         Class.forName(jdbcName);//加载数据库驱动
  18.         Connection con = DriverManager.getConnection(dbUrl, dbUserName, dbPassword);
  19.         return con;
  20.     }
  21.     /**
  22.      * 关闭连接
  23.      */
  24.     public void close(Statement stmt,Connection con) throws Exception {
  25.         if(stmt!=null) {
  26.             stmt.close();
  27.         }
  28.         if(con!=null) {
  29.             con.close();
  30.         }
  31.     }
  32. }
  34. //Demo2
  35. public class Demo2 {
  36.     private static DbUtil dbUtil = new DbUtil();
  37.     /**
  38.      * 添加图书
  39.      */
  40.     private static int addBook(String bookName,float price,String author,int bookTypeId) throws Exception {
  41.         Connection con = dbUtil.getCon();
  42.         String sql = "insert into t_book values(null,'"+bookName+"',"+price+",'"+author+"',"+bookTypeId+")";
  43.         Statement stmt = con.createStatement();//创建Statement
  44.         int result = stmt.executeUpdate(sql);
  45.         dbUtil.close(stmt, con);//关闭Statement和连接
  46.         return result;
  47.     }
  48.     public static void main(String[] args) throws Exception {
  49.         String bookName = "Java你牛";
  50.         float price = 100;
  51.         String author = "牛牛";
  52.         int bookTypeId = 1;
  53.         int result = addBook(bookName, price, author, bookTypeId);
  54.         if(result == 1) {
  55.             System.out.println("添加成功！");
  56.         }else {
  57.             System.out.println("添加失败！");
  58.         }
  59.     }
  60. }

demo3:以对象的方式

  1. //工具类
  2. public class DbUtil {
  4.     //数据库地址
  5.     private static String dbUrl="jdbc:mysql://localhost:3306/db_book";
  6.     //用户名
  7.     private static String dbUserName="root";
  8.     //密码
  9.     private static String dbPassword="root";
  10.     //驱动名称
  11.     private static String jdbcName="com.mysql.jdbc.Driver";
  13.     /**
  14.      * 获取数据库连接
  15.      *     1.加载数据库驱动
  16.      *  2.获取数据库连接
  17.      */
  18.     public Connection getCon() throws Exception {
  20.         Class.forName(jdbcName);//加载数据库驱动
  22.         Connection con = DriverManager.getConnection(dbUrl, dbUserName, dbPassword);
  24.         return con;
  25.     }
  27.     /**
  28.      * 关闭连接
  29.      */
  30.     public void close(Statement stmt,Connection con) throws Exception {
  31.         if(stmt!=null) {
  32.             stmt.close();
  33.         }
  34.         if(con!=null) {
  35.             con.close();
  36.         }
  37.     }
  38. }
  41. //book对象
  42. public class Book {
  43.     private int id;
  44.     private String bookName;
  45.     private float price;
  46.     private String author;
  47.     private int bookTypeId;
  49.     public Book(String bookName, float price, String author, int bookTypeId) {
  50.         super();
  51.         this.bookName = bookName;
  52.         this.price = price;
  53.         this.author = author;
  54.         this.bookTypeId = bookTypeId;
  55.     }
  56.         。。。//get和set方法省略
  57. }
  59. //demo3
  60. public class Demo3 {
  61.     private static DbUtil dbUtil = new DbUtil();
  63.     /**
  64.      * 添加图书2  以对象的方式
  65.      */
  66.     private static int addBook2(Book book) throws Exception{
  67.         Connection con = dbUtil.getCon();
  68.         String sql = "insert into t_book values(null,'"+book.getBookName()+"',"+book.getPrice()+",'"+book.getAuthor()+"',"+book.getBookTypeId()+")";
  69.         Statement stmt = con.createStatement();//创建Statement
  70.         int result = stmt.executeUpdate(sql);
  71.         dbUtil.close(stmt, con);//关闭Statement和连接
  72.         return result;
  73.     }
  74.     public static void main(String[] args) throws Exception {
  75.         Book book = new Book("Java牛牛2", 99, "牛牛2", 2);
  76.         int result = addBook2(book);
  78.     }
  79. }

#

三、使用Statement接口实现更新数据操作

  1. //工具类
  2. public class DbUtil {
  3.     //数据库地址
  4.     private static String dbUrl="jdbc:mysql://localhost:3306/db_book";
  5.     //用户名
  6.     private static String dbUserName="root";
  7.     //密码
  8.     private static String dbPassword="root";
  9.     //驱动名称
  10.     private static String jdbcName="com.mysql.jdbc.Driver";
  11.     /**
  12.      * 获取数据库连接
  13.      *     1.加载数据库驱动
  14.      *  2.获取数据库连接
  15.      */
  16.     public Connection getCon() throws Exception {
  18.         Class.forName(jdbcName);//加载数据库驱动
  20.         Connection con = DriverManager.getConnection(dbUrl, dbUserName, dbPassword);
  22.         return con;
  23.     }
  24.     /**
  25.      * 关闭连接
  26.      */
  27.     public void close(Statement stmt,Connection con) throws Exception {
  28.         if(stmt!=null) {
  29.             stmt.close();
  30.         }
  31.         if(con!=null) {
  32.             con.close();
  33.         }
  34.     }
  35. }
  38. //book对象
  39. public class Book {
  40.     private int id;
  41.     private String bookName;
  42.     private float price;
  43.     private String author;
  44.     private int bookTypeId;
  46.     public Book(String bookName, float price, String author, int bookTypeId) {
  47.         super();
  48.         this.bookName = bookName;
  49.         this.price = price;
  50.         this.author = author;
  51.         this.bookTypeId = bookTypeId;
  52.     }
  54.     public Book(int id, String bookName, float price, String author, int bookTypeId) {
  55.         super();
  56.         this.id = id;
  57.         this.bookName = bookName;
  58.         this.price = price;
  59.         this.author = author;
  60.         this.bookTypeId = bookTypeId;
  61.     }
  62. }
  64. //demo测试类
  65. public class Demo1 {
  66.     private static DbUtil dbUtil = new DbUtil();
  67.     private static int updateBook(Book book) throws Exception {
  68.         Connection conn = dbUtil.getCon();//获取连接
  69.         String sql = "update t_book set bookName='"+book.getBookName()
  70.                 +"',price="+book.getPrice()+",author='"+book.getAuthor()
  71.                 +"',bookTypeId="+book.getBookTypeId()+" where id="
  72.                 +book.getId();
  73.         Statement stmt = conn.createStatement();
  74.         int result = stmt.executeUpdate(sql);
  75.         dbUtil.close(stmt, conn);//关闭statemet和连接
  76.         return result;
  77.     }
  78.     public static void main(String[] args) throws Exception {
  79.         Book book = new Book(3, "java牛牛222", 123, "牛哥", 1);
  80.         int result = updateBook(book);
  81.         System.out.println("更新了"+result+"数据");
  82.         if(result==1) {
  83.             System.out.println("更新成功");
  84.         }else {
  85.             System.out.println("更新失败");
  86.         }
  87.     }
  88. }

四、使用Statement接口实现删除数据操作

  1. public class Demo2 {
  2.     private static DbUtil dbUtil = new DbUtil();
  3.     private static int deleteBook(int id) throws Exception{
  4.         Connection con = dbUtil.getCon();//获取连接
  5.         String sql = "delete from t_book where id = "+id;
  6.         Statement stmt = con.createStatement();//创建Statement
  7.         int result = stmt.executeUpdate(sql);
  8.         dbUtil.close(stmt, con);
  9.         return result;
  10.     }
  11.     public static void main(String[] args) throws Exception {
  12.         int result = deleteBook(3);
  13.         if(result ==1) {
  14.             System.out.println("删除成功！");
  15.         }else {
  16.             System.out.println("删除失败！");
  17.         }
  18.     }
  19. }

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