自定义BasicRowProcessor

之前我们使用BeanHandler封装结果集的时候，默认是表的列名和JavaBean的属性名是一致的。但是，如果表中的列名和JavaBean的属性名不一致的情况，则可以使用自定义的BasicRowProcessor对象来映射它们。

1 自定义BasicRowProcessor的示例

1.1 编写Customer实体类

Customer：

package com.yiidian.domain;

/**
 * 一点教程网 - http://www.yiidian.com
 */
public class Customer {
    private Integer id;
    private String name;
    private String gender;
    private String telephone;
    private String address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getTelephone() {
        return telephone;
    }

    public void setTelephone(String telephone) {
        this.telephone = telephone;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

1.2 编写自定义BeanHandler

CustomerHandler：

package com.yiidian.dbutils;

import com.yiidian.domain.Customer;
import org.apache.commons.dbutils.BasicRowProcessor;
import org.apache.commons.dbutils.BeanProcessor;
import org.apache.commons.dbutils.handlers.BeanHandler;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

/**
 * 一点教程网 - http://www.yiidian.com
 */
public class CustomerHandler extends BeanHandler<Customer>{

    public CustomerHandler() {
        super(Customer.class, new BasicRowProcessor(new BeanProcessor(mapColumnsToFields())));
    }

    @Override
    public Customer handle(ResultSet rs) throws SQLException {
        Customer customer = super.handle(rs);
        customer.setName("一点教程网："+customer.getName());
        return customer;
    }

    public static Map<String, String> mapColumnsToFields() {
        Map<String, String> columnsToFieldsMap = new HashMap<>();
        /**
         * key：表的列名称
         * value：JavaBean的属性名
         */
        columnsToFieldsMap.put("ID", "id");
        columnsToFieldsMap.put("NAME", "name");
        return columnsToFieldsMap;
    }
}

1.3 编写核心类

MainApp：

package com.yiidian.dbutils;

import com.yiidian.domain.Customer;
import org.apache.commons.dbutils.AsyncQueryRunner;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;
import org.apache.commons.dbutils.handlers.ArrayListHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;

import java.sql.*;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 * 一点教程网 - http://www.yiidian.com
 */
public class MainApp {
    // 驱动程序
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    // URL连接
    static final String DB_URL = "jdbc:mysql://localhost:3306/test";

    //数据库信息
    static final String USER = "root";
    static final String PASS = "root";

    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);

        CustomerHandler customerHandler = new CustomerHandler();

        try {
            Customer customer = queryRunner.query(conn, "SELECT * FROM customer WHERE name=?",
                    customerHandler, "张三");

            System.out.print("编号: " + customer.getId());
            System.out.print(", 用户名: " + customer.getName());
            System.out.print(", 性别: " + customer.getGender());
            System.out.print(", 联系电话: " + customer.getTelephone());
            System.out.println(", 住址: " + customer.getAddress());
        } finally {
            DbUtils.close(conn);
        }
    }
}

1.4 运行测试