jdbc mysql 中文乱码的解决方法

import java.sql.*;

/**
 * 使用JDBC连接数据库MySQL的过程:
 * DataBase: db_test
 * tables:   tab_test;
 * username: user_test;
 * passwd:   passwd_test;
 *
 * @author  zhongbo.wzb@alibaba-inc.com
 */
public class DBTest {

  public static Connection getConnection() throws SQLException, ClassNotFoundException {
    // 第一步：加载MySQL的JDBC的驱动
    Class.forName("com.mysql.jdbc.Driver");

    //取得连接的url,能访问MySQL数据库的用户名:user_test;密码:passwd_test, 数据库名: db_test
    String url = "jdbc:mysql://localhost:3306/db_test?useUnicode=true&characterEncoding=utf-8";
    String username = "user_test";
    String password = "passwd_test";

    // 第二步：创建与MySQL数据库的连接类的实例
    Connection conn = DriverManager.getConnection(url, username, password);
    return conn;
  }

  public static void main(String args[]) {
    System.out.println("args num: " + args.length);
    for (int i = 0; i < args.length; i++) {
      System.out.println("arg " + i + ": " + args[i]);
    }
    Connection conn = null;
    Statement statement = null;

    try {
      // 第三步：获取连接类实例con，用con创建Statement对象类实例 sql_statement
      conn = getConnection();
      statement = conn.createStatement();

      /*
      String sql_update = "insert into tab_test(province, num, timestamp) "
        + "values('山东', 2, '2014-04-18 00:00:00');" ;
      System.out.println(sql_update);
      statement.executeUpdate(sql_update);
      */

      // 第四步：执行查询，用ResultSet类的对象，返回查询的结果
      String query = "select * from tab_test;";
      ResultSet result = statement.executeQuery(query);
      while (result.next()) {
        System.out.print(result.getInt(1) + " \t| ");
        System.out.print(result.getString(2) + " \t| ");
        System.out.print(result.getInt(3) + " \t| ");
        System.out.println(result.getString(4));
      }

    } catch (ClassNotFoundException e) {
      System.err.print("ClassNotFoundException: " + e.getMessage());
      e.printStackTrace();
      System.exit(1);
    } catch (SQLException e) {
      System.err.println("SQLException: " + e.getMessage());
      e.printStackTrace();
      System.exit(1);
    } catch (Exception e) {
      System.err.print("Exception: " + e.getMessage());
      e.printStackTrace();
      System.exit(1);
    } finally { // release resources;
      try {
        if (statement != null) {
          statement.close();
          statement = null;
        }

        if (conn != null) {
          conn.close();
          conn = null;
        }
      } catch (SQLException e) {
        System.err.println("SQLException: " + e.getMessage());
        e.printStackTrace();
        System.exit(1);
      } catch (Exception e) {
        System.err.println("Exception: " + e.getMessage());
        e.printStackTrace();
        System.exit(1);
      }
    }

  }

}