Dbuils

写的Dbutils的代码

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import org.apache.commons.dbutils.ResultSetHandler;

public class DBUtil {
    static String ip = "127.0.0.1";
    static String database = "superbook";
    static String encoding = "utf8";
    static String user = "root";
    static String password = "root";
    static String port = "3306";
    private static final String driverClassName = "com.mysql.jdbc.Driver";
    
    private static boolean TESTMODE = false;//测试模式
    
    public static void enableTestMode() {//开启测试模式
        TESTMODE = true;
    }
    
    private static ThreadLocal<Connection> TL = new ThreadLocal<Connection>();//本地线程
    static {//运用静态代码块初始化加载驱动
        try {
            Class.forName(driverClassName);
        }catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    
    public static Connection getConnection() throws SQLException {//获取连接
        Connection conn = null;
        
        //从本地获取
        conn = TL.get();
        
        //拼接URL地址
        String url = String.format("jdbc:mysql://%s:%s/%s?userUnicode=true&characterEncoding=%s", ip, port, database, encoding)+"&serverTimezone=GMT%2B8&useSSL=false";
        //String url = "jdbc:mysql://localhost:3306/superbook?useUnicode=true&characterEncoding=utf-8&useSSL=false";
        System.out.println(url);
        
        //如果拿不到，或连接不可用
        if(conn==null || conn.isClosed()) {
            conn =  DriverManager.getConnection(url, user, password);
            //存到ThreadLocal中
            TL.set(conn);
        }
        
        return conn;
    }
    
    public static void startTransaction() {//关闭自动提交
        try {
            Connection conn = getConnection(); 
            if(conn != null) {
                conn.setAutoCommit(false);//设置自动提交失效
            }
        }catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }
    
    public static void commit() {//提交事务
        try {
            Connection conn = getConnection();
        if(TESTMODE) {
            return;//如果是测试模式，不进行提交
        }
        
        if(conn != null) {
            conn.commit();//提交
        }
        }catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    //关闭资源
    public static void close(ResultSet rs) {//关闭结果集
        try {
            if (rs != null)
                rs.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void close(Statement stmt) {  
        try {
            if (stmt != null)
                stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void close(Connection conn) {//关闭连接
        try {
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    public static void close() {//关闭线程连接
        try {
            close(getConnection());
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    /***
     * 
     * @param sql sql语句
     * @param params  插入的参数
     */
    public static void update(String sql, Object... params) {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            // 建立连接
            conn = getConnection();
            // 预编译SQL命令，防止sql注入
            stmt = conn.prepareStatement(sql);
            // 设置参数
            if (params != null) {
                for (int i = 0; i < params.length; i++) {
                    stmt.setObject(i + 1, params[i]);
                }
            }
            // 执行SQL
            stmt.executeUpdate();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            // 释放资源
            close(stmt);
        }
    }

    
    /***
     * 
     * @param sql sql语句
     * @param h  解析结果集，反射为对象
     * @param params sql参数
     * @return
     */
    public static <T> T select(String sql, ResultSetHandler<T> h, Object... params) {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            // 建立连接
            conn = getConnection();
            // 预编译SQL命令
            stmt = conn.prepareStatement(sql);
            // 设置参数
            if (params != null) {
                for (int i = 0; i < params.length; i++) {
                    stmt.setObject(i + 1, params[i]);
                }
            }
            // 执行SQL
            rs = stmt.executeQuery();
            // 解析结果集
            T obj = h.handle(rs);
            return obj;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            // 释放资源
            close(rs);
            close(stmt);
        }
    }
    
    
    /**
     * 根据信息查新数据
     * @param sql
     * @param params  查询参数
      * @return  返回数据
     */
    public static String select(String sql,Object... params) {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            // 建立连接
            conn = getConnection();
            // 预编译SQL命令
            stmt = conn.prepareStatement(sql);
            // 设置参数
            if (params != null) {
                for (int i = 0; i < params.length; i++) {
                    stmt.setObject(i + 1, params[i]);
                }
            }
            // 执行SQL
            rs = stmt.executeQuery();
            return rs.toString();
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            // 释放资源
            close(rs);
            close(stmt);
        }
    }
}