用Java语句创建MySQL表，并实现增、查、并利用触发器

好的，以下是用Java语句创建MySQL表的示例代码：

import java.sql.*;

public class CreateTable {
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/TESTDB";

   static final String USER = "username";
   static final String PASS = "password";

   public static void main(String[] args) {
      Connection conn = null;
      Statement stmt = null;
      try{
         Class.forName("com.mysql.jdbc.Driver");

         System.out.println("Connecting to database...");
         conn = DriverManager.getConnection(DB_URL,USER,PASS);

         System.out.println("Creating table...");
         stmt = conn.createStatement();

         String sql = "CREATE TABLE STUDENTS " +
                      "(id INTEGER not NULL, " +
                      " name VARCHAR(255), " + 
                      " age INTEGER, " + 
                      " PRIMARY KEY ( id ))"; 

         stmt.executeUpdate(sql);
         System.out.println("Table created successfully...");

         stmt.close();
         conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }catch(Exception e){
         e.printStackTrace();
      }finally{
         try{
            if(stmt!=null)
               stmt.close();
         }catch(SQLException se2){
         }
         try{
            if(conn!=null)
               conn.close();
         }catch(SQLException se){
            se.printStackTrace();
         }
      }
      System.out.println("End of program...");
   }
}

这个示例代码会连接到本地MySQL数据库的TESTDB数据库，并且创建一个名为STUDENTS的表，包含id、name和age三个字段，其中id为主键。

接下来，我们可以使用下面的代码实现增、查操作：

import java.sql.*;

public class InsertSelect {
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/TESTDB";

   static final String USER = "username";
   static final String PASS = "password";

   public static void main(String[] args) {
      Connection conn = null;
      Statement stmt = null;
      try{
         Class.forName("com.mysql.jdbc.Driver");

         System.out.println("Connecting to database...");
         conn = DriverManager.getConnection(DB_URL,USER,PASS);

         System.out.println("Inserting records into the table...");
         stmt = conn.createStatement();

         String sql = "INSERT INTO STUDENTS " +
                      "VALUES (100, 'Zara', 18)";
         stmt.executeUpdate(sql);

         sql = "INSERT INTO STUDENTS " +
                      "VALUES (101, 'Mahnaz', 22)";
         stmt.executeUpdate(sql);

         sql = "INSERT INTO STUDENTS " +
                      "VALUES (102, 'Zaid', 19)";
         stmt.executeUpdate(sql);

         sql = "INSERT INTO STUDENTS " +
                      "VALUES(103, 'Sumit', 20)";
         stmt.executeUpdate(sql);

         System.out.println("Records inserted successfully...");

         System.out.println("Fetching records from the table...");
         sql = "SELECT id, name, age FROM STUDENTS";
         ResultSet rs = stmt.executeQuery(sql);

         while(rs.next()){
            int id  = rs.getInt("id");
            String name = rs.getString("name");
            int age = rs.getInt("age");

            System.out.print("ID: " + id);
            System.out.print(", Name: " + name);
            System.out.print(", Age: " + age);
            System.out.println();
         }
         rs.close();

         stmt.close();
         conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }catch(Exception e){
         e.printStackTrace();
      }finally{
         try{
            if(stmt!=null)
               stmt.close();
         }catch(SQLException se2){
         }
         try{
            if(conn!=null)
               conn.close();
         }catch(SQLException se){
            se.printStackTrace();
         }
      }
      System.out.println("End of program...");
   }
}

这个示例代码会向STUDENTS表中插入四条记录，并且查询所有记录并输出。

最后，我们可以使用下面的代码实现一个简单的触发器，当向STUDENTS表中插入新记录时，自动向另一个表中插入一条记录：

import java.sql.*;

public class TriggerExample {
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost/TESTDB";

   static final String USER = "username";
   static final String PASS = "password";

   public static void main(String[] args) {
      Connection conn = null;
      Statement stmt = null;
      try{
         Class.forName("com.mysql.jdbc.Driver");

         System.out.println("Connecting to database...");
         conn = DriverManager.getConnection(DB_URL,USER,PASS);

         System.out.println("Creating trigger...");
         stmt = conn.createStatement();

         String sql = "CREATE TRIGGER insert_record " +
                      "AFTER INSERT ON STUDENTS " +
                      "FOR EACH ROW " +
                      "INSERT INTO STUDENTS_LOG " +
                      "VALUES (new.id, new.name, new.age)";

         stmt.executeUpdate(sql);

         System.out.println("Trigger created successfully...");

         System.out.println("Inserting records into the table...");
         stmt = conn.createStatement();

         sql = "INSERT INTO STUDENTS " +
                      "VALUES (104, 'John', 21)";
         stmt.executeUpdate(sql);

         System.out.println("Record inserted successfully...");

         System.out.println("Fetching records from the table...");
         sql = "SELECT id, name, age FROM STUDENTS_LOG";
         ResultSet rs = stmt.executeQuery(sql);

         while(rs.next()){
            int id  = rs.getInt("id");
            String name = rs.getString("name");
            int age = rs.getInt("age");

            System.out.print("ID: " + id);
            System.out.print(", Name: " + name);
            System.out.print(", Age: " + age);
            System.out.println();
         }
         rs.close();

         stmt.close();
         conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }catch(Exception e){
         e.printStackTrace();
      }finally{
         try{
            if(stmt!=null)
               stmt.close();
         }catch(SQLException se2){
         }
         try{
            if(conn!=null)
               conn.close();
         }catch(SQLException se){
            se.printStackTrace();
         }
      }
      System.out.println("End of program...");
   }
}

这个示例代码会创建一个名为insert_record的触发器，当向STUDENTS表中插入新记录时，自动向STUDENTS_LOG表中插入一条记录，然后插入一条新记录并查询STUDENTS_LOG表中的所有记录并输出。

需要注意的是，这些示例代码中的数据库连接参数需要根据实际情况进行修改。