带参数模版方法实现机制

近日,在研究 Spring ，看到模板方法有这样一段代码：

 一时没有搞明白，经过仔细研究 发现可以用内部类来实现,而Spring

时用接口来实现的。以下时我写的内部类的实现方法：

---

 

mysql:

create database school;

use school;

create table student
(
    stu_id int not null primary key,
    stu_name varchar(20) not null,
    stu_age int
);

select * from student;

 

---

 

 

applicationContext.xml：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>
    <bean id="dataSource"
        class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName">
            <value>com.mysql.jdbc.Driver</value>
        </property>
        <property name="url">
            <value>jdbc:mysql:///school</value>
        </property>
        <property name="username">
            <value>root</value>
        </property>
    </bean>
</beans>

---

DriverManager.java

package test;

import javax.sql.DataSource;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class DriverManager ...{
    public DataSource getDataSource() ...{
        ApplicationContext context = new ClassPathXmlApplicationContext(
                "applicationContext.xml");

        javax.sql.DataSource dataSource = (DataSource) context
                .getBean("dataSource");

        return dataSource;

    }

    public static void main(String[] args) ...{
        javax.sql.DataSource d = new DriverManager().getDataSource();

        System.out.println(d);
    }
}

---

JdbcTemplate.java

package test;

import java.sql.PreparedStatement;
import java.sql.SQLException;

import javax.sql.DataSource;

public class JdbcTemplate ...{
    private DataSource dataSource;

    public JdbcTemplate(DataSource dataSource) ...{
        super();
        this.dataSource = dataSource;
    }

    static class PreparedStatementSetter ...{
        protected java.sql.PreparedStatement pstmt;

        public void setValues(PreparedStatement pstmt) throws SQLException ...{
            this.pstmt = pstmt;
        }
    }

    public void insert(String sql, PreparedStatementSetter pss) ...{
        try ...{
            java.sql.Connection con = dataSource.getConnection();
            java.sql.PreparedStatement pstmt = con.prepareStatement(sql);

            try ...{
                pss.setValues(pstmt);
            } catch (Exception e) ...{
                // TODO 自动生成 catch 块
                e.printStackTrace();
            }
            pstmt.executeUpdate();

            pstmt.close();
            con.close();

        } catch (Exception e) ...{
            // TODO 自动生成 catch 块
            e.printStackTrace();
        }

    }

    public static void main(String[] args) ...{

        DriverManager d = new DriverManager();
        javax.sql.DataSource dataSource = d.getDataSource();

        JdbcTemplate template = new JdbcTemplate(dataSource);

        String sql = "insert into student values (?,?,?)";

        template.insert(sql, new PreparedStatementSetter() ...{
            public void setValues(PreparedStatement pstmt) ...{
                try ...{
                    pstmt.setInt(1, 1112);
                    pstmt.setString(2, "aaaaaaaaaa");
                    pstmt.setInt(3, 19);
                } catch (Exception e) ...{
                    // TODO 自动生成 catch 块
                    e.printStackTrace();
                }

            }
        });
    }

}