BaseJDBCとCRUDDAOの書き方の実例コード

まずBASEJDBCの書き方例を見ます。

package com.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import com.mysql.jdbc.Driver;
public class BaseJDBC {
 //                 
 private final String DRIVER = "com.mysql.jdbc.Driver";
 //                                 
 private final String URL = "jdbc:mysql://localhost:3306/zzy";//           
 //          
 private final String USERNMAE = "root";
 //         
 private final String PASSWORD = "root";
 /**
  *          
  * 
  * @return
  */
 public Connection getConnection() {
  try {
   //Driver d=new Driver();
   //     ：  （         ）
   Class.forName(DRIVER);
   //             
   return DriverManager.getConnection(URL, USERNMAE, PASSWORD);
  } catch (ClassNotFoundException e) {
   //e.printStackTrace("            ");
  } catch (SQLException e) {
   //        
   e.printStackTrace();
  }
  return null;
 }
 /**
  *         
  * @param con
  * @param st
  * @param rt
  */
 public void closeAll(Connection con, Statement st, ResultSet rt) {
  try {
   if (rt != null) {
    rt.close();
    rt = null;
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }
  try {
   if (st != null) {
    st.close();
    st = null;
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }
  try {
   if (con != null) {
    con.close();
    con = null;
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }
 }
}

CRUDDAO書き方コードの例：

package com.dao;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.sql.*;
import java.util.*;
import java.util.Map.Entry;
/**
 * 
 * @author zzy
 *
 * 2016 12 1   1:49:49
 */
public class CRUDDAO<T> extends BaseJDBC {
 private Connection con = null;
 private PreparedStatement pt = null;
 private Statement st = null;
 private ResultSet rt = null;
 private Class<T> c;
 public CRUDDAO() {
 }
 public CRUDDAO(Class<T> c) {
  this.c = c;
 }
 /**
  *              ：         ：        
  * 
  * @param <T>
  * @param <T>
  * 
  * @return Map<Integer, List<T>>
  */
 public Map<Integer, List<T>> selectAll(Map<String, Object[]> m) {
  int index = 0;
  Map<Integer, List<T>> map = new LinkedHashMap<Integer, List<T>>();
  List<T> list = null;
  try {
   con = super.getConnection();
   if (con != null) {
    Set<Entry<String, Object[]>> set = m.entrySet();
    for (Entry<String, Object[]> entry : set) {
     list = new ArrayList<T>();
     pt = con.prepareStatement(entry.getKey());
     this.bind(entry.getValue());
     rt = pt.executeQuery();
     while (rt.next()) {
      list.add(this.toBean2());
     }
     map.put(++index, list);
    }
   } else {
    System.out.println("       ");
   }
  } catch (SQLException e) {
   e.printStackTrace();
  } finally {
   super.closeAll(con, pt, rt);
  }
  return map;
 }
 /**
  *                               
  * 
  * @return
  */
 private T toBean() {
  T t = null;
  try {
   t = c.newInstance();
   Method[] m = c.getMethods();
   ResultSetMetaData rmt = rt.getMetaData();
   for (int i = 1, count = rmt.getColumnCount(); i <= count; i++) {
    String columName = rmt.getColumnName(i);
    columName = "set" + columName.substring(0, 1).toUpperCase()
      + columName.substring(1);
    for (int j = 0; j < m.length; j++) {
     if (columName.equals(m[j].getName())) {
      m[j].invoke(t, rt.getObject(i));
      break;
     }
    }
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  return t;
 }
 private T toBean2() {
  T t = null;
  try {
   //         
   t = c.newInstance();
   //        
   Field[] field = c.getDeclaredFields();
   for (Field f : field) {
    //                   
    Object value = rt.getObject(f.getName());
    f.setAccessible(true);//            
    f.set(t, value);//           set        
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  return t;
 }
 /**
  *     
  * 
  * @param obj
  */
 private void bind(Object[] obj) {
  try {
   if (obj != null) {
    for (int i = 0, k = obj.length; i < k; i++) {
     pt.setObject(i + 1, obj[i]);
    }
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }
 }
 /**
  *                                  
  * 
  * @param name
  * @param id
  * @return
  */
 public int[] updateAll(Map<String, Object[]> map) {
  int[] row = new int[map.size()];
  int index = 0;
  int error = 0;
  try {
   con = super.getConnection();
   if (con != null) {
    Set<Entry<String, Object[]>> set = map.entrySet();
    //               
    con.setAutoCommit(false);
    for (Entry<String, Object[]> entry : set) {
     pt = con.prepareStatement(entry.getKey());
     this.bind(entry.getValue());
     row[index] = pt.executeUpdate();
     if (row[index] == 0) {
      throw new Exception("    ，    ！");
     }
     index++;
    }
   } else {
    System.out.println("       ");
   }
  } catch (Exception e) {
   error++;
   e.printStackTrace();
  } finally {
   if (error > 0) {
    try {
     //             
     con.rollback();
    } catch (SQLException e) {
     e.printStackTrace();
    }
   } else {
    try {
     //     
     con.commit();
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }
   super.closeAll(con, st, null);
  }
  return row;
 }
}

締め括りをつける
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