由于现在发现做个小项目都是导入n多的依赖包,很烦琐,只想快点开发完一个个的小需求项目,这个时候真心不想用框架,只能自己写个jdbcutils,虽然网上有很多有apache的,阿里的,但是感觉用过后都不怎么顺手,然后自己花了点时间写个新的,不喜勿喷
1.我们要写个resultset集合转成bean的回调接口,这个用过spring jdbc的人都知道这玩意
package org.simple.mvc.jdbc.bean; import java.sql.ResultSet; import java.sql.SQLException; public interface RowMapper<T> { public abstract T mapRow(ResultSet rs) throws SQLException; }
2.先来个基本的jdbc操作接口吧,这样好规范点
package org.simple.mvc.jdbc; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.List; import java.util.Map; import javax.sql.DataSource; import org.simple.mvc.jdbc.bean.RowMapper; public interface JdbcOperation { /** * update或delete功能 * * @param sql * @param params * @return 变更记录数 * @throws SQLException */ public abstract int execute(String sql, Object[] params) throws SQLException; /** * update或delete功能 * * @param sql * @return 变更记录数 * @throws SQLException */ public abstract int execute(String sql) throws SQLException; /** * 批处理update或delete功能 * * @param sql * @param params * @return 变更记录数 * @throws SQLException */ public abstract int executeBatch(String sql, List<Object[]> params) throws SQLException; /** * 批处理update或delete功能 * * @param sql * @param params * @return 变更记录数 * @throws SQLException */ public abstract int executeBatch(String sql) throws SQLException; /** * select功能 * * @param sql * @param params * @return 原生ResultSet数据集合 * @throws SQLException */ public abstract ResultSet queryForResultSet(String sql, Object[] params) throws SQLException; /** * select功能 * * @param sql * @return 原生ResultSet数据集合 * @throws SQLException */ public abstract ResultSet queryForResultSet(String sql) throws SQLException; /** * select功能 * * @param sql * @param params * @return List<?>数据集合 * @throws SQLException */ public abstract List<?> queryForBean(String sql, Object[] params, RowMapper<?> mapper) throws SQLException; /** * select功能 * * @param sql * @param params * @return List<?>数据集合 * @throws SQLException */ public abstract List<?> queryForBean(String sql, RowMapper<?> mapper) throws SQLException; /** * select功能 * * @param sql * @param params * @return List<Map<String, Object>>数据集合 * @throws SQLException */ public abstract List<Map<String, Object>> queryForMap(String sql, Object[] params) throws SQLException; /** * select功能 * * @param sql * @param params * @return List<Map<String, Object>>数据集合 * @throws SQLException */ public abstract List<Map<String, Object>> queryForMap(String sql) throws SQLException; /** * select功能 * * @param sql * @return 统计单列记录数 * @throws SQLException */ public abstract int queryForInt(String sql, Object[] params) throws SQLException; /** * select功能 * * @param sql * @return 统计单列记录数 * @throws SQLException */ public abstract int queryForInt(String sql) throws SQLException; /** * 释放Connection资源 * * @param x */ public abstract void free(Connection x); /** * 释放Statement资源 * * @param x */ public abstract void free(Statement x); /** * 释放PreparedStatement资源 * * @param x */ public abstract void free(PreparedStatement x); /** * 释放ResultSet资源 * * @param x */ public abstract void free(ResultSet x); /** * 设置数据源 * * @param dataSource */ public abstract void setDataSource(DataSource dataSource); /** * 获取数据库链接 * * @return Connection */ public abstract Connection getConnection(); /** * 获取数据库链接 * * @param autoCommit * @return Connection */ public Connection getConnection(boolean autoCommit); }
3.实现我们接口里面的方法
package org.simple.mvc.jdbc.impl; import java.sql.Connection; 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; import javax.sql.DataSource; import org.simple.mvc.jdbc.JdbcOperation; import org.simple.mvc.jdbc.bean.RowMapper; /** * 简易JDBC实现类 * * @author shadow * */ public class SimpleJdbc implements JdbcOperation { private static final boolean AUTO_COMMIT = true; private DataSource dataSource; public SimpleJdbc() { } public SimpleJdbc(DataSource dataSource) { this.dataSource = dataSource; } public Connection getConnection() { return getConnection(AUTO_COMMIT); } public Connection getConnection(boolean autoCommit) { try { Connection conn = dataSource.getConnection(); if (!autoCommit) conn.setAutoCommit(autoCommit); return conn; } catch (SQLException e) { e.printStackTrace(); } return null; } @Override public int execute(String sql, Object[] params) throws SQLException { Connection conn = getConnection(false); PreparedStatement stmt = null; int result = -1; try { stmt = createPreparedStatement(conn, sql, params); result = stmt.executeUpdate(); conn.commit(); } catch (Exception e) { conn.rollback(); e.printStackTrace(); } finally { free(stmt); free(conn); } return result; } @Override public int execute(String sql) throws SQLException { return execute(sql, new Object[] {}); } @Override public ResultSet queryForResultSet(String sql, Object[] params) throws SQLException { Connection conn = getConnection(); PreparedStatement stmt = null; try { stmt = createPreparedStatement(conn, sql, params); return stmt.executeQuery(); } catch (Exception e) { e.printStackTrace(); } finally { free(stmt); free(conn); } return null; } @Override public ResultSet queryForResultSet(String sql) throws SQLException { return queryForResultSet(sql, new Object[] {}); } @Override public int queryForInt(String sql, Object[] params) throws SQLException { Connection conn = getConnection(); PreparedStatement stmt = null; ResultSet rs = null; try { stmt = createPreparedStatement(conn, sql, params); rs = createResultSet(stmt); while (rs.next()) { return rs.getInt(1); } } catch (Exception e) { e.printStackTrace(); } finally { free(rs); free(stmt); free(conn); } return 0; } @Override public int queryForInt(String sql) throws SQLException { return queryForInt(sql, new Object[] {}); } @Override public List<?> queryForBean(String sql, Object[] params, RowMapper<?> mapper) throws SQLException { Connection conn = getConnection(); PreparedStatement stmt = null; ResultSet rs = null; List<Object> list = null; try { stmt = createPreparedStatement(conn, sql, params); rs = createResultSet(stmt); list = new ArrayList<Object>(); while (rs.next()) { list.add(mapper.mapRow(rs)); } } catch (Exception e) { e.printStackTrace(); } finally { free(rs); free(stmt); free(conn); } return list; } @Override public List<?> queryForBean(String sql, RowMapper<?> mapper) throws SQLException { return queryForBean(sql, new Object[] {}, mapper); } @Override public List<Map<String, Object>> queryForMap(String sql, Object[] params) throws SQLException { Connection conn = getConnection(); PreparedStatement stmt = null; ResultSet rs = null; try { stmt = createPreparedStatement(conn, sql, params); rs = createResultSet(stmt); List<Map<String, Object>> list = new ArrayList<Map<String, Object>>(); Map<String, Object> map = null; ResultSetMetaData rsd = rs.getMetaData(); int columnCount = rsd.getColumnCount(); while (rs.next()) { map = new HashMap<String, Object>(columnCount); for (int i = 1; i < columnCount; i++) { map.put(rsd.getColumnName(i), rs.getObject(i)); } list.add(map); } return list; } catch (Exception e) { e.printStackTrace(); } finally { free(rs); free(stmt); free(conn); } return null; } @Override public List<Map<String, Object>> queryForMap(String sql) throws SQLException { return queryForMap(sql, new Object[] {}); } @Override public int executeBatch(String sql, List<Object[]> params) throws SQLException { int result = 0; Connection conn = getConnection(false); PreparedStatement stmt = null; try { stmt = conn.prepareStatement(sql); for (int i = 0; i < params.size(); i++) { Object[] param = params.get(i); for (int j = 0; j < param.length; j++) stmt.setObject(j + 1, param[j]); stmt.addBatch(); if (i % 1000 == 0) { stmt.executeBatch(); stmt.clearBatch(); } } stmt.executeBatch(); conn.commit(); result = params.size(); } catch (Exception e) { conn.rollback(); e.printStackTrace(); } finally { free(stmt); free(conn); } return result; } @Override public int executeBatch(String sql) throws SQLException { return executeBatch(sql, new ArrayList<Object[]>()); } public DataSource getDataSource() { return dataSource; } public void setDataSource(DataSource dataSource) { this.dataSource = dataSource; } @Override public void free(Connection x) { if (x != null) try { x.close(); } catch (SQLException e) { e.printStackTrace(); } } @Override public void free(Statement x) { if (x != null) try { x.close(); } catch (SQLException e) { e.printStackTrace(); } } @Override public void free(PreparedStatement x) { if (x != null) try { x.close(); } catch (SQLException e) { e.printStackTrace(); } } @Override public void free(ResultSet x) { if (x != null) try { x.close(); } catch (SQLException e) { e.printStackTrace(); } } public PreparedStatement createPreparedStatement(Connection conn, String sql, Object[] params) throws SQLException { PreparedStatement stmt = conn.prepareStatement(sql); for (int i = 0; i < params.length; i++) stmt.setObject(i + 1, params[i]); return stmt; } public ResultSet createResultSet(PreparedStatement stmt) throws SQLException { return stmt.executeQuery(); } }
package org.simple.mvc.jdbc.source; import java.io.PrintWriter; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.LinkedList; import javax.sql.DataSource; /** * 简易连接池实现类 * * @author shadow * */ public class SimpleDataSource implements DataSource { private int poolSize = 5; private LinkedList<Connection> pool = new LinkedList<Connection>(); public SimpleDataSource(String driver, String url, String name, String pwd) { this(driver, url, name, pwd, 5); } public SimpleDataSource(String driver, String url) { this(driver, url, "", "", 5); } public SimpleDataSource(String driver, String url, String name, String pwd, int poolSize) { try { Class.forName(driver); this.poolSize = poolSize; if (poolSize <= 0) { throw new RuntimeException("初始化池大小失败: " + poolSize); } for (int i = 0; i < poolSize; i++) { Connection con = DriverManager.getConnection(url, name, pwd); con = ConnectionProxy.getProxy(con, pool);// 获取被代理的对象 pool.add(con);// 添加被代理的对象 } } catch (Exception e) { throw new RuntimeException(e.getMessage(), e); } } /** 获取池大小 */ public int getPoolSize() { return poolSize; } /** 不支持日志操作 */ public PrintWriter getLogWriter() throws SQLException { throw new RuntimeException("Unsupport Operation."); } public void setLogWriter(PrintWriter out) throws SQLException { throw new RuntimeException("Unsupport operation."); } /** 不支持超时操作 */ public void setLoginTimeout(int seconds) throws SQLException { throw new RuntimeException("Unsupport operation."); } public int getLoginTimeout() throws SQLException { return 0; } @SuppressWarnings("unchecked") public <T> T unwrap(Class<T> iface) throws SQLException { return (T) this; } public boolean isWrapperFor(Class<?> iface) throws SQLException { return DataSource.class.equals(iface); } /** 从池中取一个连接对象,使用了同步和线程调度 */ public Connection getConnection() throws SQLException { synchronized (pool) { if (pool.size() == 0) { try { pool.wait(); } catch (InterruptedException e) { throw new RuntimeException(e.getMessage(), e); } return getConnection(); } else { return pool.removeFirst(); } } } public Connection getConnection(String username, String password) throws SQLException { throw new RuntimeException("不支持接收用户名和密码的操作"); } /** 实现对Connection的动态代理 */ static class ConnectionProxy implements InvocationHandler { private Object obj; private LinkedList<Connection> pool; private ConnectionProxy(Object obj, LinkedList<Connection> pool) { this.obj = obj; this.pool = pool; } public static Connection getProxy(Object o, LinkedList<Connection> pool) { Object proxed = Proxy.newProxyInstance(o.getClass().getClassLoader(), new Class[] { Connection.class }, new ConnectionProxy(o, pool)); return (Connection) proxed; } public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if (method.getName().equals("close")) { synchronized (pool) { pool.add((Connection) proxy); pool.notify(); } return null; } else { return method.invoke(obj, args); } } } }
public static void main(String[] args) throws SQLException { SimpleDataSource dataSource = new SimpleDataSource("org.sqlite.JDBC", "jdbc:sqlite:/E:p1010.db"); SimpleJdbc jdbc = new SimpleJdbc(dataSource); List<User> list = (List<User>) jdbc.queryForBean("select * from t_user", new RowMapper<User>() { User user = null; @Override public User mapRow(ResultSet rs) throws SQLException { user = new User(); user.setId(rs.getInt("id")); user.setUsername(rs.getString("username")); return user; } }); for (User user : list) { System.out.println(user.getId() + "---" + user.getUsername()); } }