JDBC PrepareStatement物件執行批次處理範例

以下是使用PrepareStatement物件進行批次處理的典型步驟順序 -

• 使用預留位置建立SQL語句。
• 使用prepareStatement()方法建立PrepareStatement物件。
• 使用setAutoCommit()將自動提交設定為false。
• 使用addBatch()方法在建立的Statement物件上新增SQL語句到批次處理中。
• 在建立的Statement物件上使用executeBatch()方法執行所有SQL語句。
• 最後，使用commit()方法提交所有更改。

此範例程式碼是基於前面章節中完成的環境和資料庫設定編寫的。

以下程式碼片段提供了使用PrepareStatement物件的批次更新範例，將下面程式碼儲存到檔案：BatchingWithPrepareStatement.java -

// Import required packages
// See more detail at /20/213/8320.html

import java.sql.*;

public class BatchingWithPrepareStatement {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
   static final String DB_URL = "jdbc:mysql://localhost/EMP";

   //  Database credentials
   static final String USER = "root";
   static final String PASS = "123456";

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

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

      // Create SQL statement
      String SQL = "INSERT INTO Employees(id,first,last,age) " +
                   "VALUES(?, ?, ?, ?)";

      // Create preparedStatemen
      System.out.println("Creating statement...");
      stmt = conn.prepareStatement(SQL);

      // Set auto-commit to false
      conn.setAutoCommit(false);

      // First, let us select all the records and display them.
      printRows( stmt );

      // Set the variables
      stmt.setInt( 1, 400 );
      stmt.setString( 2, "Python" );
      stmt.setString( 3, "Zhang" );
      stmt.setInt( 4, 33 );
      // Add it to the batch
      stmt.addBatch();

      // Set the variables
      stmt.setInt( 1, 401 );
      stmt.setString( 2, "C++" );
      stmt.setString( 3, "Huang" );
      stmt.setInt( 4, 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();

      // Again, let us select all the records and display them.
      printRows( stmt );

      // Clean-up environment
      stmt.close();
      conn.close();
   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            stmt.close();
      }catch(SQLException se2){
      }// nothing we can do
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");
}//end main

public static void printRows(Statement stmt) throws SQLException{
   System.out.println("Displaying available rows...");
   // Let us select all the records and display them.
   String sql = "SELECT id, first, last, age FROM Employees";
   ResultSet rs = stmt.executeQuery(sql);

   while(rs.next()){
      //Retrieve by column name
      int id  = rs.getInt("id");
      int age = rs.getInt("age");
      String first = rs.getString("first");
      String last = rs.getString("last");

      //Display values
      System.out.print("ID: " + id);
      System.out.print(", Age: " + age);
      System.out.print(", First: " + first);
      System.out.println(", Last: " + last);
   }
   System.out.println();
   rs.close();
}//end printRows()
}//end JDBCExample

編譯上面程式碼，如下 -

F:\worksp\jdbc>javac -Djava.ext.dirs=F:\worksp\jdbc\libs BatchingWithPrepareStatement.java

執行上面程式碼如下所示 -

F:\worksp\jdbc>javac -Djava.ext.dirs=F:\worksp\jdbc\libs BatchingWithPrepareStatement.java

F:\worksp\jdbc>java -Djava.ext.dirs=F:\worksp\jdbc\libs BatchingWithPrepareStatement
Connecting to database...
Thu Jun 01 04:46:38 CST 2017 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Creating statement...
Displaying available rows...
ID: 100, Age: 35, First: Max, Last: Su
ID: 101, Age: 25, First: Wei, Last: Wang
ID: 102, Age: 35, First: Xueyou, Last: Zhang
ID: 103, Age: 30, First: Jack, Last: Ma
ID: 106, Age: 28, First: Curry, Last: Stephen
ID: 107, Age: 32, First: Kobe, Last: Bryant
ID: 200, Age: 30, First: Curry, Last: Stephen
ID: 201, Age: 35, First: Kobe, Last: Bryant

Displaying available rows...
ID: 100, Age: 35, First: Max, Last: Su
ID: 101, Age: 25, First: Wei, Last: Wang
ID: 102, Age: 35, First: Xueyou, Last: Zhang
ID: 103, Age: 30, First: Jack, Last: Ma
ID: 106, Age: 28, First: Curry, Last: Stephen
ID: 107, Age: 32, First: Kobe, Last: Bryant
ID: 200, Age: 30, First: Curry, Last: Stephen
ID: 201, Age: 35, First: Kobe, Last: Bryant
ID: 400, Age: 33, First: Python, Last: Zhang
ID: 401, Age: 31, First: C++, Last: Huang

Goodbye!

F:\worksp\jdbc>