androidj常用数据库操作JDBC Utils

package mypackage;import java.lang.reflect.Field;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.ResultSetMetaData;import java.sql.SQLException;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class JDBCUtils {private final String USERNAME = "root";private final String PWD = "admin";private final String DRIVER = "com.mysql.jdbc.Driver";private Connection connection;private java.sql.PreparedStatement preparedStatement;private ResultSet resultset;private String URL = "jdbc:mysql://localhost:3306/mydb";public JDBCUtils() {try {Class.forName(DRIVER);System.out.println("注册驱动成功");} catch (Exception e) {// TODO: handle exception}}// 定义获得数据库的链接public Connection getConnection() {try {connection = DriverManager.getConnection(URL, USERNAME, PWD);} catch (Exception e) {// TODO: handle exception}return connection;}/** *  * @param sql * @param params * @return * @throws SQLException */public boolean updateByPrepareStatement(String sql, List<Object> params)throws SQLException {boolean flag = false;int result = -1;// 受影响的行数int index = 1;preparedStatement = connection.prepareStatement(sql);if (params != null && !params.isEmpty()) {for (int i = 0; i < params.size(); i++) {preparedStatement.setObject(index++, params.get(i));}}result = preparedStatement.executeUpdate();flag = result > 0 ? true : false;return flag;}/** * 查询返回单条记录 *  * @param sql * @param params * @return * @throws SQLException */public Map<String, Object> findSimpleResult(String sql, List<Object> params)throws SQLException {Map<String, Object> map = new HashMap<String, Object>();int index = 1;preparedStatement = connection.prepareStatement(sql);if (params != null && !params.isEmpty()) {for (int i = 0; i < params.size(); i++) {preparedStatement.setObject(index++, params.get(i));}}resultset = preparedStatement.executeQuery();// 返回查询结果ResultSetMetaData metaData = resultset.getMetaData();int col_len = metaData.getColumnCount();while (resultset.next()) {for (int i = 0; i < col_len; i++) {String col_name = metaData.getColumnName(i + 1);Object col_values = resultset.getObject(col_name);if (col_values == null) {col_values = "";}map.put(col_name, col_values);}}return map;}/** * 查找多条记录 *  * @return */public List<Map<String, Object>> findMoreResultString(String sql,List<Object> params) throws SQLException {List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();int index = 1;preparedStatement = connection.prepareStatement(sql);if (params != null && !params.isEmpty()) {for (int i = 0; i < params.size(); i++) {preparedStatement.setObject(index++, params.get(i));}}resultset = preparedStatement.executeQuery();// 返回查询结果ResultSetMetaData metaData = resultset.getMetaData();int col_len = metaData.getColumnCount();while (resultset.next()) {Map<String, Object> map = new HashMap<String, Object>();for (int i = 0; i < col_len; i++) {String col_name = metaData.getColumnName(i + 1);Object col_values = resultset.getObject(col_name);if (col_values == null) {col_values = "";}map.put(col_name, col_values);}list.add(map);}return list;}// 利用反射机制/** * 通过反射机制访问数据库 *  * @param sql * @param params * @param cls * @return * @throws SQLException * @throws Exception * @throws IllegalAccessException */public <T> List<T> findMore(String sql, List<Object> params, Class<T> cls)throws SQLException, Exception {List<T> list = new ArrayList<T>();int index = 1;Object resultObject=null;preparedStatement = connection.prepareStatement(sql);if (params != null && !params.isEmpty()) {for (int i = 0; i < params.size(); i++) {preparedStatement.setObject(index++, params.get(i));}}resultset = preparedStatement.executeQuery();// 返回查询结果ResultSetMetaData metaData = resultset.getMetaData();int col_len = metaData.getColumnCount();while (resultset.next()) {resultObject = cls.newInstance();for (int i = 0; i < col_len; i++) {String col_name = metaData.getColumnName(i+1);Object col_values = resultset.getObject(col_name);if (col_values == null) {col_values = "";}Field field = cls.getDeclaredField(col_name);field.setAccessible(true);field.set(resultObject, col_values);}list.add((T) resultObject);}return list;}/** * 关闭数据库连接 */public void releaseConnection() {if (resultset != null)try {resultset.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}if (preparedStatement != null)try {preparedStatement.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}if (connection != null)try {connection.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** *  * @param args * @throws SQLException */public static void main(String[] args) throws SQLException {JDBCUtils jdbcUtils = new JDBCUtils();jdbcUtils.getConnection();/* * String sql = "insert into userinfo(username,pwd) values (?,?)"; * List<Object> params = new ArrayList<Object>(); params.add("admin"); * params.add("admin"); boolean flag = * jdbcUtils.updateByPrepareStatement(sql, params); * System.out.println(flag); */String sql = "select * from userinfo where id=?";String sql1 = "select * from userinfo";List<Object> params = new ArrayList<Object>();/*params.add(1);Map map = jdbcUtils.findSimpleResult(sql, params);try {List list = jdbcUtils.findMoreResultString(sql1, null);System.out.println(map);System.out.println(list);}catch (Exception e) {e.printStackTrace();} finally {jdbcUtils.releaseConnection();}*/try {System.out.println("---fsdfas");List<userinfo> userlist=jdbcUtils.findMore(sql1, null, userinfo.class);System.out.println("---"+userlist);} catch (Exception e) {e.printStackTrace();}finally {jdbcUtils.releaseConnection();}}}
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