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package com.bh.nora.util; import java.lang.reflect.Field; import java.lang.reflect.Method; 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.sql.Statement; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class JDBCUtils { private static final String noraUrl = "jdbc:mysql://localhost:3306/db_test_d?useSSL=false&serverTimezone=GMT%2B8"; private static final String noraName = "root"; private static final String noraPass = "123456"; /** * 获取数据库连接 * @throws SQLException */ public static Connection getConnection() throws SQLException { return DriverManager.getConnection(noraUrl, noraName, noraPass); } @SuppressWarnings("unchecked") public static <T> T get(String sql, Object [] args) throws SQLException { Connection noraConn = JDBCUtils.getConnection(); PreparedStatement noraPs = noraConn.prepareStatement(sql); for(int i = 0; i < args.length; i++) { noraPs.setObject(i + 1, args[i]); } ResultSet noraRs = noraPs.executeQuery(); Object o = null; if (noraRs.next()) { o = noraRs.getObject(1); destory(noraConn, noraPs, noraRs); return (T)o; } return null; } public static <E> List<E> selectCondiation(String sql, Class<E> clazz, Object [] args) throws Exception { Connection noraConn = JDBCUtils.getConnection(); PreparedStatement noraPs = noraConn.prepareStatement(sql); for(int i = 0; i < args.length; i++) { noraPs.setObject(i + 1, args[i]); } ResultSet noraRs = noraPs.executeQuery(); ResultSetMetaData noraRsmd = noraRs.getMetaData(); int columnCount = noraRsmd.getColumnCount(); List<E> results = new ArrayList<E>(); while(noraRs.next()) { E o = clazz.getConstructor().newInstance(); for (int i = 0 ; i < columnCount; i++) { String columnLabel = noraRsmd.getColumnLabel(i + 1); Object columnValue = noraRs.getObject(columnLabel); Field field = clazz.getDeclaredField(columnLabel); Method method = clazz.getMethod(setMethod(columnLabel), field.getType()); method.invoke(o, columnValue); } results.add(o); } destory(noraConn, noraPs, noraRs); return results; } public static String setMethod(String methodName) { return "set" + methodName.substring(0, 1).toUpperCase() + methodName.substring(1); } public static List<Map<String, Object>> selectCondiationByMap(String sql, Object [] args) throws Exception { Connection noraConn = JDBCUtils.getConnection(); PreparedStatement noraPs = noraConn.prepareStatement(sql); for(int i = 0; i < args.length; i++) { noraPs.setObject(i + 1, args[i]); } ResultSet noraRs = noraPs.executeQuery(); ResultSetMetaData noraNsmd = noraRs.getMetaData(); int columnCount = noraNsmd.getColumnCount(); List<Map<String, Object>> results = new ArrayList<Map<String, Object>>(); while(noraRs.next()) { Map<String, Object> map = new HashMap<String, Object>(); for (int i = 0 ; i < columnCount; i++) { String columnLabel = noraRsmd.getColumnLabel(i + 1); Object columnValue = noraRs.getObject(columnLabel); map.put(columnLabel, columnValue); } results.add(map); } destory(noraConn, noraPs, noraRs); return results; } public static void destory(Connection noraConn, Statement noraSt, ResultSet noraRs) { if(noraRs != null) { try { noraRs.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (noraSt != null) { try { noraSt.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (noraConn != null) { try { noraConn.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }