模拟ibtais参数注入的过程

使用Ibatis时，只需要把sql语句写好，指明需要注入的参数对应对象中的属性就可以了。这样极大的提高了开发效率。

我在工作过程中，遇到了一些场景，需要自己去直接连接JDBC写数据库，我又想模拟Ibatis自动补全参数的功能，所以就写了下面的这些代码。欢迎指证批评。

 

创建数据库连接的代码

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

/**
 * 2012-8-9 tracy.liuy
 */
public class DbConnection {


    public Connection conn = null;

    public DbConnection(String driver, String url, String user, String password){
        try {
            // 注册驱动程序类
            Class.forName(driver);
            // 1、初始化连接对象
            conn = DriverManager.getConnection(url, user, password);
            // 2、设置连接对象的自动提交模式
            conn.setAutoCommit(false);
        } catch (Exception e) {
            throw new RuntimeException("get connect failed", e);
        }
    }
}

 

 

 

Customer对象

/**
 * 2012-8-15 tracy.liuy
 */
public class Customer {

    private Long   custId;
    private String name;

    public Long getCustId() {
        return custId;
    }

    public void setCustId(Long custId) {
        this.custId = custId;
    }

    public String getName() {
        return name;
    }

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

}

 

 

批量修改的代码

 

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;



/**
 * 
 * 2012-8-15
 * tracy.liuy
 */
public class IBatis {

    /**
     * @param sql
     * @param campaignBdLogList 2012-8-1 tracy.liuy
     * @throws InvocationTargetException
     * @throws IllegalAccessException
     * @throws NoSuchMethodException
     * @throws IllegalArgumentException
     * @throws SecurityException
     */
    public int updateBatch(List objList) {
        
        DbConnection dbC = new DbConnection("com.mysql.jdbc.Driver", "address",  
                                            "username", "password");  

        PreparedStatement stmt = null;
        int rows = 0;

        if (objList != null && objList.size() != 0) {
            return rows;
        }
        //ibatis中的sql语句
        String sql = "update coustomer set name=#name# where custid = #custId#";
        
        //1.将 sql语句中 ## 及之间的内容替换成 ?,即  update coustomer set name=? where custid = ? 
        String prepareSql = placeSomeCharacter(sql);

        try {
            
            //2.创建连接
            stmt = dbC.conn.prepareStatement(prepareSql);
            for (Object obj : objList) {
                //3.补全参数（详细介绍看下面的代码）
                this.fillStatementBatch(stmt, sql, obj);
                rows += stmt.executeUpdate();
            }

        } catch (SQLException e) {
            throw new RuntimeException(sql + " update failed", e);

        } catch (Exception e) {
            throw new RuntimeException(sql + " update failed", e);
        }

        finally {
            close(stmt);
        }

        return rows;

    }

    /**
     * 使用正则表达式，替换需要注入的内容
     * @param sql
     * @return
     * 2012-8-2
     * tracy.liuy
     */
    private String placeSomeCharacter(String sql) {
       return sql.replaceAll("#.+?#", "?");
    }
    
    /**
     * 将对象中的属性根据sql语句中指定的一一替换PreparedStatement中的?号
     * @param stmt
     * @param obj 2012-8-1 tracy.liuy
     * @param obj2
     * @throws SQLException
     * @throws NoSuchMethodException
     * @throws SecurityException
     * @throws InvocationTargetException
     * @throws IllegalAccessException
     * @throws IllegalArgumentException
     */
    private void fillStatementBatch(PreparedStatement stmt, String sql, Object obj) throws SQLException,
                                                                                   SecurityException,
                                                                                   NoSuchMethodException,
                                                                                   IllegalArgumentException,
                                                                                   IllegalAccessException,
                                                                                   InvocationTargetException {
        char c = '#';
        int begin = 0;
        List<Integer> indexList = new ArrayList<Integer>();

        while (true) {
            int index = sql.indexOf(c, begin);
            if (index == -1) {
                break;
            }
            indexList.add(index);
            begin = index+1;
        }

        List<String> props = new ArrayList<String>();

        for (int i = 0; i < indexList.size(); i += 2) {
            props.add(sql.substring(indexList.get(i)+1, indexList.get(i + 1)));
        }
        int i = 1;
        for (String prop : props) {
            stmt.setObject(i++, getProperties(obj, prop));
        }

    }

    /**
     * @param obj
     * @param prop
     * @return 2012-8-1 tracy.liuy
     * @throws NoSuchMethodException
     * @throws SecurityException
     * @throws InvocationTargetException
     * @throws IllegalAccessException
     * @throws IllegalArgumentException
     */
    @SuppressWarnings({ "rawtypes", "unchecked" })
    private Object getProperties(Object obj, String prop) throws SecurityException, NoSuchMethodException,
                                                         IllegalArgumentException, IllegalAccessException,
                                                         InvocationTargetException {
        Method metd = null;
        Class clazz = obj.getClass();
        metd = clazz.getMethod("get" + change(prop), null);
        if (metd != null) {
            return metd.invoke(obj, null);
        }
        return null;
    }

    /**
     * @param src 源字符串
     * @return 字符串，将src的第一个字母转换为大写，src为空时返回null
     */
    public String change(String src) {
        if (src != null) {
            StringBuffer sb = new StringBuffer(src);
            sb.setCharAt(0, Character.toUpperCase(sb.charAt(0)));
            return sb.toString();
        } else {
            return null;
        }
    }
    

    /**
     * 关闭结果集
     * 
     * @param rs 结果集
     */
    protected void close(ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                throw new RuntimeException("rs close failed", e);
            }
        }
    }
    
    
    /**
     * 关闭语句对象
     * 
     * @param stmt 语句对象
     */
    protected void close(Statement stmt) {
        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                throw new RuntimeException("stmt close failed", e);
            }
        }
    }

}