package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.ResourceBundle;
public class Jdbc {
private static ResourceBundle res = ResourceBundle.getBundle("jdbc");
private static String url = res.getString("db.url");
private static String user = res.getString("db.user");
private static String psw = res.getString("db.password");
private static String driverClass = res.getString("driverClass");
private static Integer poolSize = Integer.parseInt(res.getString("poolSize"));
private static LinkedList<Connection> connections = new LinkedList<Connection>();
private Connection conn;
private ResultSet rs;
private ResultSetMetaData md;
private PreparedStatement ps;
private List<Map<String,Object>> list;
private Map<String,Object> map;
static{
try {
Class.forName(driverClass);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
initConnPool();
}
//初始化连接池
private static void initConnPool() {
for (int i = 0; i < poolSize ; i++) {
try {
Connection conn = DriverManager.getConnection(url, user, psw);
connections.add(conn);
} catch (SQLException e) {
e.printStackTrace();
}
}
}
//拿出一个连接
private synchronized void getConnection() {
conn = connections.removeFirst();
}
//放回一个连接
private synchronized void backConnection(Connection connection,PreparedStatement ps,ResultSet rs) {
try {
if(ps!=null) ps.close();
if(rs!=null) rs.close();
connections.addLast(connection);
} catch (SQLException e) {
e.printStackTrace();
}
}
//执行数据查询语句
public List<Map<String,Object>> dql(String sql,Object...objs){
getConnection();
list = new ArrayList<Map<String,Object>>();
try {
ps = conn.prepareStatement(sql);
for (int i = 1; i <= objs.length; i++) {
ps.setObject(i, objs[i]);
}
rs = ps.executeQuery();
md = rs.getMetaData();
while (rs.next()) {
map = new HashMap<String,Object>();
for (int i = 1; i <= md.getColumnCount(); i++) {
String key = md.getColumnName(i);
Object value = rs.getObject(i);
map.put(key, value);
}
list.add(map);
}
} catch (SQLException e) {
e.printStackTrace();
}finally {
backConnection(conn,ps,rs);
}
return list;
}
//执行数据管理语句
public boolean dml(String sql,Object...objs){
getConnection();
try {
ps = conn.prepareStatement(sql);
for (int i = 1; i <= objs.length; i++) {
ps.setObject(i, objs[i]);
}
return ps.executeUpdate()==1?true:false;
} catch (SQLException e) {
e.printStackTrace();
}finally {
backConnection(conn,ps,rs);
}
return false;
}
}
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