Java 和 MySQL – 使用 PrepareStatement 对象进行批处理

这是将批处理与 PrepareStatement 对象一起使用的典型步骤序列 –

• 使用占位符创建 SQL 语句。

• 使用任一prepareStatement() 方法创建 PrepareStatement 对象。

• 使用setAutoCommit()将自动提交设置为 false 。

• 在创建的语句对象上使用addBatch()方法将尽可能多的 SQL 语句添加到批处理中。

• 在创建的语句对象上使用executeBatch()方法执行所有 SQL 语句。

• 最后，使用commit()方法提交所有更改。

此示例代码是根据前几章中完成的环境和数据库设置编写的。

将以下示例复制并粘贴到 TestApplication.java 中，编译并运行如下 –

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class TestApplication {
   static final String DB_URL = "jdbc:mysql://localhost/TUTORIALSPOINT";
   static final String USER = "guest";
   static final String PASS = "guest123";
   static final String INSERT_QUERY = "INSERT INTO Employees(first,last,age) VALUES(?, ?, ?)";

   public static void printResultSet(ResultSet rs) throws SQLException{
      // Ensure we start with first row
      rs.beforeFirst();
      while(rs.next()){
         // Display values
         System.out.print("ID: " + rs.getInt("id"));
         System.out.print(", Age: " + rs.getInt("age"));
         System.out.print(", First: " + rs.getString("first"));
         System.out.println(", Last: " + rs.getString("last"));
      }
      System.out.println();
   }

   public static void main(String[] args) {
      // Open a connection
      try(Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
         PreparedStatement stmt = conn.prepareStatement(INSERT_QUERY,
            ResultSet.TYPE_SCROLL_INSENSITIVE,
            ResultSet.CONCUR_UPDATABLE)
      ) {		      
         conn.setAutoCommit(false);	    	  

         ResultSet rs = stmt.executeQuery("Select * from Employees");
         printResultSet(rs);

         // Set the variables
         stmt.setString( 1, "Pappu" );
         stmt.setString( 2, "Singh" );
         stmt.setInt( 3, 33 );
         // Add it to the batch
         stmt.addBatch();

         // Set the variables
         stmt.setString( 1, "Pawan" );
         stmt.setString( 2, "Singh" );
         stmt.setInt( 3, 31 );
         // Add it to the batch
         stmt.addBatch();

         // Create an int[] to hold returned values
         int[] count = stmt.executeBatch();

         //Explicitly commit statements to apply changes
         conn.commit();

         rs = stmt.executeQuery("Select * from Employees");
         printResultSet(rs);	  

         stmt.close();
         rs.close();

      } catch (SQLException e) {
         e.printStackTrace();
      } 
   }
}

现在让我们编译上面的例子如下 –

C:\>javac TestApplication.java
C:\>

当您运行TestApplication 时，它会产生以下结果 –

C:\>java TestApplication
ID: 1, Age: 23, First: Zara, Last: Ali
ID: 2, Age: 30, First: Mahnaz, Last: Fatma
ID: 3, Age: 35, First: Zaid, Last: Khan
ID: 4, Age: 33, First: Sumit, Last: Mittal
ID: 5, Age: 40, First: John, Last: Paul
ID: 7, Age: 35, First: Sita, Last: Singh
ID: 8, Age: 20, First: Rita, Last: Tez
ID: 9, Age: 20, First: Sita, Last: Singh
ID: 10, Age: 30, First: Zia, Last: Ali
ID: 11, Age: 35, First: Raj, Last: Kumar

ID: 1, Age: 23, First: Zara, Last: Ali
ID: 2, Age: 30, First: Mahnaz, Last: Fatma
ID: 3, Age: 35, First: Zaid, Last: Khan
ID: 4, Age: 33, First: Sumit, Last: Mittal
ID: 5, Age: 40, First: John, Last: Paul
ID: 7, Age: 35, First: Sita, Last: Singh
ID: 8, Age: 20, First: Rita, Last: Tez
ID: 9, Age: 20, First: Sita, Last: Singh
ID: 10, Age: 30, First: Zia, Last: Ali
ID: 11, Age: 35, First: Raj, Last: Kumar
ID: 12, Age: 33, First: Pappu, Last: Singh
ID: 13, Age: 31, First: Pawan, Last: Singh
C:\>