Android 之JDBC

  1 package com.jdbc.dbUtils;
  2 
  3 import java.lang.reflect.Field;
  4 import java.sql.Connection;
  5 import java.sql.DriverManager;
  6 import java.sql.PreparedStatement;
  7 import java.sql.ResultSet;
  8 import java.sql.ResultSetMetaData;
  9 import java.sql.SQLException;
 10 import java.util.ArrayList;
 11 import java.util.HashMap;
 12 import java.util.List;
 13 import java.util.Map;
 14 
 15 import com.jdbc.dbUtils.dormain.UserInfo;
 16 
 17 
 18 
 19 public class JDBCutils {
 20 
 21     private final String USERNAME="root";
 22     private final String PASSWORD="admin";
 23     private final String DRIVER="com.mysql.jdbc.Driver";
 24     private final String URL="jdbc:mysql://localhost:3306/mydb";
 25      
 26     private Connection connection;
 27     private PreparedStatement preparedStatement;
 28     private ResultSet resultSet;
 29     
 30     public JDBCutils() {
 31         try {
 32             Class.forName(DRIVER);//注册驱动
 33             System.out.println("成功注册驱动");
 34             
 35         } catch (Exception e) {
 36             // TODO: handle exception
 37         }
 38     }
 39 
 40     public Connection getConnection(){
 41         try {
 42             connection=DriverManager.getConnection(URL,USERNAME, PASSWORD);
 43         } catch (Exception e) {
 44             // TODO: handle exception
 45             e.printStackTrace();
 46         }
 47         return connection;
 48     }
 49     //增删改
 50     public boolean updateByPreparedStatement(String sql,List<Object> params)throws SQLException {
 51         boolean flag=false;
 52         int result=-1;//执行增删改操作的时候所影响的行数
 53         int index=1;//占位符的第一个位置
 54         preparedStatement=connection.prepareStatement(sql);
 55         if(params!=null&&!params.isEmpty()){
 56             for (int i = 0; i < params.size(); i++) {
 57                 preparedStatement.setObject(index++, params.get(i));
 58             }
 59         }
 60         result=preparedStatement.executeUpdate();
 61         flag=result>0?true:false;
 62         return flag;
 63     }
 64     //查询 返回单条记录
 65     public Map<String,Object> findSimpleResult(String sql,List<Object> params) throws SQLException{
 66         Map<String,Object> map=new HashMap<String,Object>();
 67         int index=1;//占位符的第一个位置
 68         preparedStatement=connection.prepareStatement(sql);
 69         if(params!=null&&!params.isEmpty()){
 70             for (int i = 0; i < params.size(); i++) {
 71                 preparedStatement.setObject(index++, params.get(i));
 72             }
 73         }
 74         resultSet=preparedStatement.executeQuery();
 75         ResultSetMetaData resultSetMetaData=resultSet.getMetaData();
 76         int col_len=resultSetMetaData.getColumnCount();//得到数据库表的列
 77         while(resultSet.next()){
 78             for (int i = 0; i < col_len; i++) {
 79                 String col_name=resultSetMetaData.getColumnName(i+1);
 80                 Object col_val=resultSet.getObject(col_name);
 81                 if(col_val==null){
 82                     col_val="";
 83                 }
 84                 map.put(col_name,col_val);
 85             }
 86         }
 87         return map;
 88         
 89     }
 90     //查询 返回多条记录
 91     public List<Map<String,Object>> findMultiResult(String sql,List<Object> params) throws SQLException{
 92         List<Map<String,Object>> list=new ArrayList<Map<String,Object>>();
 93         int index=1;//占位符的第一个位置
 94         preparedStatement=connection.prepareStatement(sql);
 95         if(params!=null&&!params.isEmpty()){
 96             for (int i = 0; i < params.size(); i++) {
 97                 preparedStatement.setObject(index++, params.get(i));
 98             }
 99         }
100         resultSet=preparedStatement.executeQuery();
101         ResultSetMetaData resultSetMetaData=resultSet.getMetaData();
102         int col_len=resultSetMetaData.getColumnCount();//得到数据库表的列名
103         while(resultSet.next()){
104             Map<String,Object>map=new HashMap<String,Object>();
105             for (int i = 0; i < col_len; i++) {
106                 String col_name=resultSetMetaData.getColumnName(i+1);
107                 Object col_val=resultSet.getObject(col_name);
108                 if(col_val==null){
109                     col_val="";
110                 }
111                 map.put(col_name,col_val);
112             }
113             list.add(map);
114         }
115         return list;
116         
117     }
118     //jdbc的封装也可以采用反射机制
119     public <T> T findSimpReflectResult(String sql,List<Object> params,Class<T> cls) throws Exception{
120         T resObj=null;
121         int index=1;//占位符的第一个位置
122         preparedStatement=connection.prepareStatement(sql);
123         if(params!=null&&!params.isEmpty()){
124             for (int i = 0; i < params.size(); i++) {
125                 preparedStatement.setObject(index++, params.get(i));
126             }
127         }
128         resultSet=preparedStatement.executeQuery();
129         ResultSetMetaData resultSetMetaData=resultSet.getMetaData();
130         int col_len=resultSetMetaData.getColumnCount();//得到数据库表的列名
131         while(resultSet.next()){
132             resObj=cls.newInstance();//通过反射机制创建实例
133             for (int i = 0; i < col_len; i++) {
134                 String col_name=resultSetMetaData.getColumnName(i+1);
135                 Object col_val=resultSet.getObject(col_name);
136                 if(col_val==null){
137                     col_val="";
138                 }
139                 Field field=cls.getDeclaredField(col_name);
140                 field.setAccessible(true);//打开访问javabean的私有权限
141                 field.set(resObj, col_val);
142             }
143         }
144         return resObj;
145     }
146     public <T> List<T> findMultiReflectResult(String sql,List<Object> params,Class<T> cls) throws Exception{
147         List<T> list=new ArrayList<T>();
148         int index=1;//占位符的第一个位置
149         preparedStatement=connection.prepareStatement(sql);
150         if(params!=null&&!params.isEmpty()){
151             for (int i = 0; i < params.size(); i++) {
152                 preparedStatement.setObject(index++, params.get(i));
153             }
154         }
155         resultSet=preparedStatement.executeQuery();
156         ResultSetMetaData resultSetMetaData=resultSet.getMetaData();
157         int col_len=resultSetMetaData.getColumnCount();//得到数据库表的列名
158         while(resultSet.next()){
159             T resObj=cls.newInstance();//通过反射机制创建实例
160             for (int i = 0; i < col_len; i++) {
161                 String col_name=resultSetMetaData.getColumnName(i+1);
162                 Object col_val=resultSet.getObject(col_name);
163                 if(col_val==null){
164                     col_val="";
165                 }
166                 Field field=cls.getDeclaredField(col_name);
167                 field.setAccessible(true);//打开访问javabean的私有权限
168                 field.set(resObj, col_val);
169             }
170             list.add(resObj);
171         }
172         return list;
173     }
174     public void releaseConnection() throws SQLException{
175         if(resultSet!=null){
176             resultSet.close();
177         }
178         if(preparedStatement!=null){
179             preparedStatement.close();
180         }
181         if(connection!=null){
182             connection.close();
183         }
184     }
185     public static void main(String[] args) throws Exception {
186         // TODO Auto-generated method stub
187         JDBCutils jdbc=new JDBCutils();
188         jdbc.getConnection();
189         List<Object> params=new ArrayList<Object>();
190     
191         /*    params.add("fjf");
192         params.add("123");
193         params.add("fanjingfang");
194         String sql="insert into userinfo(username,password,realname)values(?,?,?)";
195         boolean flag=jdbc.updateByPreparedStatement(sql, params);
196         System.out.println(flag);
197         params.add(1);
198         String sql="select * from userinfo where id=?";
199         Map<String,Object> m=jdbc.findSimpleResult(sql, params);
200         System.out.println(m);*/
201         
202         /*String sql2="select * from userinfo ";
203         List<Map<String,Object>> list=jdbc.findMultiResult(sql2, null);
204         System.out.println(list);*/
205         
206     /*    params.add(1);
207         String sql3="select * from userinfo where id=? ";
208         UserInfo u=jdbc.findSimpReflectResult(sql3, params,UserInfo.class);
209         System.out.println(u);*/
210         
211         String sql4="select * from userinfo ";
212         List<UserInfo> list=jdbc.findMultiReflectResult(sql4, null,UserInfo.class);
213         System.out.println(list);
214     }
215 
216 }