JDBC——DBHelper代码模版
时间：2021-07-01 10:21:17
帮助过：10人阅读
com.oolong.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.List;
import java.util.Map;
public class DBHelper {
private String driverName = "com.mysql.jdbc.Driver"
;
private String url = "jdbc:mysql://localhost:3306/hrms?useSSL=true"
;
private String userName = "root"
;
private String password = "1234"
;
private Connection conn;
private static DBHelper dbHelper;
public static Connection getConnection(){
if (dbHelper ==
null) {
DBHelper.dbHelper =
new DBHelper();
}
return dbHelper.conn;
}
private DBHelper() {
try {
Class.forName(driverName);
this.conn =
DriverManager.getConnection(url, userName, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static int executeUpdate(String sql, String[] param) {
Connection conn =
null;
PreparedStatement pst =
null;
int res = 0
;
try{
conn =
DBHelper.getConnection();
pst =
conn.prepareStatement(sql);
for (
int i = 0; i < param.length; i++
) {
pst.setString(i+1
, param[i]);
}
res =
pst.executeUpdate();
pst.close();
conn.close();
} catch (SQLException ex) {
ex.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return res;
}
public static List<Map<String, Object>>
executeQuery(String sql) {
return executeQuery(sql,
new String[0
]);
}
public static List<Map<String, Object>>
executeQuery(String sql, String[] param) {
Connection conn =
null;
PreparedStatement pst =
null;
ResultSet rs =
null;
List<Map<String, Object>> resut =
new ArrayList<>
();
Map<String, Object> map =
null;
try{
conn =
DBHelper.getConnection();
pst =
conn.prepareStatement(sql);
for (
int i = 0; i < param.length; i++
) {
pst.setString(i+1
, param[i]);
}
rs =
pst.executeQuery();
ResultSetMetaData rsm =
rs.getMetaData();
String[] columns =
new String[rsm.getColumnCount()];
for (
int i = 0; i < rsm.getColumnCount(); i++
) {
columns[i] = rsm.getColumnName(i + 1
);
}
rs.beforeFirst();
while(rs.next()) {
map =
new HashMap<>
();
for(String col : columns) {
map.put(col, rs.getObject(col));
}
resut.add(map);
}
rs.close();
pst.close();
conn.close();
} catch (SQLException ex) {
ex.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return resut;
}
}
JDBC——DBHelper代码模版
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