如何在Java中使用预处理语句？（How to use prepared statement in Java?）

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2023-12-01

问题描述 (Problem Description)

如何在java中使用Prepared Statement？

解决方案 (Solution)

以下示例使用PrepareStatement方法创建PreparedStatement。它还使用PreparedStatement的setInt和setString方法来设置PreparedStatement的参数。

import java.sql.*;
public class jdbcConn {
   public static void main(String[] args) throws Exception {
      Class.forName("org.apache.derby.jdbc.ClientDriver");
      Connection con = DriverManager.getConnection ( 
         "jdbc:derby://localhost:1527/testDb","name","pass");
      PreparedStatement updateemp = con.prepareStatement(
         "insert into emp values(?,?,?)");
      updateemp.setInt(1,23);
      updateemp.setString(2,"Roshan");
      updateemp.setString(3, "CEO");
      updateemp.executeUpdate();
      Statement stmt = con.createStatement();
      String query = "select * from emp";
      ResultSet rs =  stmt.executeQuery(query);
      System.out.println("Id Name    Job");
      while (rs.next()) {
         int id = rs.getInt("id");
         String name = rs.getString("name");
         String job = rs.getString("job");
         System.out.println(id + "  " + name+"   "+job);
      }      
   }
}

结果 (Result)

上面的代码示例将产生以下结果。结果可能会有所不同。

Id Name    Job
23  Roshan   CEO