Dbutils 简明教程

Apache Commons DBUtils - Update Query

以下示例将演示如何使用 DBUtils 借助 Update 查询来更新记录。我们将在 Employees 表中更新一条记录。

The following example will demonstrate how to update a record using Update query with the help of DBUtils. We’ll update a record in Employees Table.

Syntax

更新查询的语法如下 −

The syntax for update query is as follows −

String updateQuery = "UPDATE employees SET age=? WHERE id=?";
int updatedRecords = queryRunner.update(conn, updateQuery, 33,104);

其中，

Where,

  1. updateQuery − Update query having placeholders.

  2. queryRunner − QueryRunner object to update employee object in database.

为了了解与 DBUtils 相关的上述概念，让我们编写一个将运行更新查询的示例。为了编写我们的示例，让我们创建一个示例应用程序。

To understand the above mentioned concepts related to DBUtils, let us write an example which will run an update query. To write our example, let us create a sample application.

Step

Description

1

Update the file MainApp.java created under chapter DBUtils - First Application.

2

Compile and run the application as explained below.

以下是 Employee.java 的内容。

Following is the content of the Employee.java.

public class Employee {
   private int id;
   private int age;
   private String first;
   private String last;
   public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }
   public int getAge() {
      return age;
   }
   public void setAge(int age) {
      this.age = age;
   }
   public String getFirst() {
      return first;
   }
   public void setFirst(String first) {
      this.first = first;
   }
   public String getLast() {
      return last;
   }
   public void setLast(String last) {
      this.last = last;
   }
}

以下是 MainApp.java 文件的内容。

Following is the content of the MainApp.java file.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;

public class MainApp {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
   static final String DB_URL = "jdbc:mysql://localhost:3306/emp";

   // Database credentials
   static final String USER = "root";
   static final String PASS = "admin";
   public static void main(String[] args) throws SQLException {
      Connection conn = null;
      QueryRunner queryRunner = new QueryRunner();
      DbUtils.loadDriver(JDBC_DRIVER);
      conn = DriverManager.getConnection(DB_URL, USER, PASS);
      try {
         int updatedRecords = queryRunner.update(conn,
            "UPDATE employees SET age=? WHERE id=?", 33,104);
         System.out.println(updatedRecords + " record(s) updated.");
      } finally {
         DbUtils.close(conn);
      }
   }
}

一旦完成创建源文件，我们就来运行应用程序。如果你的应用程序一切正常，它将打印出以下消息 −

Once you are done creating the source files, let us run the application. If everything is fine with your application, it will print the following message −

1 record(s) updated.