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

以下是使用 PrepareStatement 对象进行批处理的典型步骤序列 −

• 使用占位符创建 SQL 语句。

• 使用 prepareStatement() 方法创建 PrepareStatement 对象。

• 使用 setAutoCommit() 将自动提交设置为 false。

• 使用 addBatch() 方法在创建的语句对象上将任意数量的 SQL 语句添加到批处理中。

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

• 最后，使用 commit() 提交所有更改方法。

此示例代码是根据前面章节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，然后按如下方式编译并运行 −

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{
      // 确保我们从第一行开始
      rs.beforeFirst();
      while(rs.next()){
         // 显示值
         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) {
      // 打开连接
      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);

        // 设置变量
        stmt.setString( 1, "Pappu" );
        stmt.setString( 2, "Singh" );
        stmt.setInt( 3, 33 );
        // 将其添加到批处理中
        stmt.addBatch();
        
        // 设置变量
        stmt.setString( 1, "Pawan" );
        stmt.setString( 2, "Singh" );
        stmt.setInt( 3, 31 );
        // 将其添加到批处理中
        stmt.addBatch();
        
        // 创建一个 int[] 来保存返回值
        int[] count = stmt.executeBatch();
        
        // 明确提交语句以应用更改
        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:\>