java连接mysql底层封装详解

本文实例为大家分享了java连接mysql底层封装代码，供大家参考，具体内容如下

连接数据库

package com.dao.db;

import java.sql.connection;
import java.sql.sqlexception;

/**
 * 数据库连接层mysql
 * @author administrator
 *
 */
public class dbconnection {
 
 
 /**
  * 连接数据库
  * @return
  */
 public static connection getdbconnection()
 {
  // 1. 注册驱动
  try {
   class.forname("com.mysql.jdbc.driver");
  } catch (classnotfoundexception e) {
   // todo auto-generated catch block
   e.printstacktrace();
  }
  // 获取数据库的连接
  try {
   connection conn = java.sql.drivermanager.getconnection("jdbc:mysql://localhost/mysql?useunicode=true&characterencoding=utf-8", "root", "root");
   return conn;
  } catch (sqlexception e1) {
   e1.printstacktrace();
  }
  return null;
 }
 
}

数据层封装

package com.dao.db;

import java.sql.connection;
import java.sql.preparedstatement;
import java.sql.resultset;
import java.sql.resultsetmetadata;
import java.sql.sqlexception;
import java.sql.types;
import java.util.arraylist;
import java.util.hashmap;

/**
 * mysql数据库底层封装
 * @author administrator
 *
 */
public class dbmanager {
 
 private preparedstatement pstmt;
 private connection conn;
 private resultset rs;
 

 /**
  * 打开数据库
  */
 public dbmanager() {
  conn = dbconnection.getdbconnection();
 }
 
 /**
  * 执行修改添加操作
  * @param coulmn
  * @param type
  * @param sql
  * @return
  * @throws sqlexception
  */
 public boolean updateoradd(string[] coulmn, int[] type, string sql) throws sqlexception
 {
  if(!setpstmtparam(coulmn, type, sql))
   return false;
  boolean flag = pstmt.executeupdate()>0?true:false;
  closedb();
  return flag;
 }
 /**
  * 获取查询结果集
  * @param coulmn
  * @param type
  * @param sql
  * @throws sqlexception
  */
 public datatable getresultdata(string[] coulmn, int[] type, string sql) throws sqlexception
 {
  datatable dt = new datatable();
  
  arraylist<hashmap<string, string>>list = new arraylist<hashmap<string, string>>();
  
  if(!setpstmtparam(coulmn, type, sql))
   return null;
  rs = pstmt.executequery();
  resultsetmetadata rsmd = rs.getmetadata();//取数据库的列名 
  int numberofcolumns = rsmd.getcolumncount();
  while(rs.next())
  {
   hashmap<string, string> rstree = new hashmap<string, string>(); 
   for(int r=1;r<numberofcolumns+1;r++)
    {
    rstree.put(rsmd.getcolumnname(r),rs.getobject(r).tostring());
    }
   list.add(rstree);
  }
  closedb();
  dt.setdatatable(list);
  return dt;
 }
 
 /**
  * 参数设置
  * @param coulmn
  * @param type
  * @throws sqlexception 
  * @throws numberformatexception 
  */
 private boolean setpstmtparam(string[] coulmn, int[] type, string sql) throws numberformatexception, sqlexception
 {
  if(sql== null) return false;
  pstmt = conn.preparestatement(sql);
  if(coulmn != null && type != null && coulmn.length !=0 && type.length !=0 )
  {  
   for (int i = 0; i<type.length; i++) {
    switch (type[i]) {
    case types.integer:
     pstmt.setint(i+1, integer.parseint(coulmn[i]));
     break;
    case types.boolean:
     pstmt.setboolean(i+1, boolean.parseboolean(coulmn[i]));
     break;
    case types.char:
     pstmt.setstring(i+1, coulmn[i]);
     break;
    case types.double:
     pstmt.setdouble(i+1, double.parsedouble(coulmn[i]));
     break;
    case types.float:
     pstmt.setfloat(i+1, float.parsefloat(coulmn[i]));
     break;
    default:
     break;
    }
   }
  }
  return true;
 }
 
 /**
  * 关闭数据库
  * @throws sqlexception
  */
 private void closedb() throws sqlexception
 {
  if(rs != null)
  {
   rs.close();
  }
  if(pstmt != null)
  {
   pstmt.close();
  }
  if(conn != null)
  {
   conn.close();
  }
  
 }
}

数据集封装

package com.dao.db;

import java.util.arraylist;
import java.util.hashmap;
import java.util.iterator;
import java.util.map;
import java.util.set;

/**
 * 数据集封装
 * @author administrator
 *
 */
public class datatable {
 
 public string[] column;//列字段
 public string[][] row; //行值
 public int rowcount = 0;//行数
 public int colcoun = 0;//列数
 
 
 public datatable() {
  super();
 }
 
 public datatable(string[] column, string[][] row, int rowcount, int colcoun) {
  super();
  this.column = column;
  this.row = row;
  this.rowcount = rowcount;
  this.colcoun = colcoun;
 }


 public void setdatatable(arraylist<hashmap<string, string>> list) {
  rowcount = list.size();
  colcoun = list.get(0).size();
  column = new string[colcoun];
  row = new string[rowcount][colcoun];
  for (int i = 0; i < rowcount; i++) {
   set<map.entry<string, string>> set = list.get(i).entryset();
   int j = 0;
   for (iterator<map.entry<string, string>> it = set.iterator(); it
     .hasnext();) {
    map.entry<string, string> entry = (map.entry<string, string>) it
      .next();
    row[i][j] = entry.getvalue();
    if (i == rowcount - 1) {
     column[j] = entry.getkey();
    }
    j++;
   }
  }
 }

 public string[] getcolumn() {
  return column;
 }

 public void setcolumn(string[] column) {
  this.column = column;
 }

 public string[][] getrow() {
  return row;
 }

 public void setrow(string[][] row) {
  this.row = row;
 }

 public int getrowcount() {
  return rowcount;
 }

 public void setrowcount(int rowcount) {
  this.rowcount = rowcount;
 }

 public int getcolcoun() {
  return colcoun;
 }

 public void setcolcoun(int colcoun) {
  this.colcoun = colcoun;
 }
 
 

}

测试demo

package com.bussiness.test;

import java.sql.sqlexception;
import java.sql.types;

import com.dao.db.dbmanager;
import com.dao.db.datatable;

public class testbusiness{
 
 static string searchsql = "select * from score";
 static string insertsql = "insert into score(name, age, score)values(?,?,?)";
 static string deletesql = "delete from score where id = ?";
 static string updatesql = "update score set name = ? where id = ?";
 
 public static void main(string[] args) {
  intsertdata();
  searchdata();
 }
 
 private static void intsertdata()
 { 
  dbmanager dm = new dbmanager();
  string[] coulmn = new string[]{"wyf2", "23", "89.5"};
  int[] type = new int[]{types.char, types.integer, types.double};
  
  try {
   boolean flag = dm.updateoradd(coulmn, type, insertsql);
   if(flag)
    system.out.println("插入成功");
  } catch (sqlexception e) {
   e.printstacktrace();
  }
 }
 private static void searchdata()
 { 
  dbmanager dm = new dbmanager();
  string[] coulmn = null;
  int[] type = null;
  
  try {
   datatable dt = dm.getresultdata(coulmn, type, searchsql);
   if(dt != null && dt.getrowcount()> 0){   
    for(int i = 0; i<dt.getrowcount(); i++)
    {
     for(int j = 0; j<dt.getcolcoun(); j++)
     system.out.printf(dt.getrow()[i][j]+"\t");
     system.out.println();
    }
   }
   else
    system.out.println("查询失败");
  } catch (sqlexception e) {
   e.printstacktrace();
  }
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。