jdbc简单封装类

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实现最简单的JDBC的封装

只需要三个类 JDBCUtil BaseDaoJdbc BaseDaoJdbcImpl

1. [代码]JDBC配置文件

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#============================#

#===== Database sttings =====#

#============================#

#mysql database setting

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc:mysql://localhost:3306/database?useUnicode=true&characterEncoding=utf-8

jdbc.username=root

jdbc.password=root

2. [代码]JDBCUtil

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public class JDBCUtil {

// 日志接口

private static Logger logger = LoggerFactory.getLogger(JDBCUtil.class);

//JDBC配置属性

private static Properties ps = new Properties();

// 配置文件位置

private static final String db_setting = "/config/acs-db.properties";

// 初始化JDBC配置文件属性

static{

try {

if(JDBCUtil.class.getResourceAsStream(db_setting) == null){

if(logger.isInfoEnabled())logger.info("请调用 getInstance(clazz) 方法！ ");

}else{

ps.load(JDBCUtil.class.getResourceAsStream(db_setting));

// 加载JDBC驱动

Class.forName(ps.getProperty("jdbc.driver"));

if(logger.isInfoEnabled())logger.info("JDBC驱动启动成功! "+ps.getProperty("jdbc.driver"));

}

} catch (IOException | ClassNotFoundException e) {

logger.error(e.getMessage(),e);

}

private JDBCUtil(){}

private static JDBCUtil jdbcUtil = new JDBCUtil();

/**

*

* getInstance(获取JDBCUtil实例)

* (注意事项：同项目下调用 – 可选)

* @return

* @exception

* @since 1.0.0

*/

public static JDBCUtil getInstance(){

return jdbcUtil;

}

/**

* getInstance(获取JDBCUtil实例)

* (注意事项：不同项目下调用 – 可选)

* @param clazz 调用类字节码

* @return

* @throws IOException

* @exception

* @since 1.0.0

*/

public static JDBCUtil getInstance(Class<?> clazz) throws IOException{

if(clazz.getResourceAsStream(db_setting) == null)

throw new RuntimeException("acs-db.properties is not found ") ;

ps.load(clazz.getResourceAsStream(db_setting));

// 加载JDBC驱动

try {

Class.forName(ps.getProperty("jdbc.driver"));

} catch (ClassNotFoundException e) {

logger.error(e.getMessage(),e);

}

return jdbcUtil;

}

/**

*

* getConnection(获取数据库连接)

* (注意事项：-无)

* @return

* @exception

* @since 1.0.0

*/

public Connection getConnection(){

Connection conn = null;

try {

conn = DriverManager.getConnection(ps.getProperty("jdbc.url"),

ps.getProperty("jdbc.username"), ps.getProperty("jdbc.password"));

} catch (SQLException e) {

logger.error(e.getMessage(),e);

}

return conn;

}

// JDBC BASE DAO

private BaseDaoJdbc baseDaoJdbc = new BaseDaoJdbcimpl();

/**

* getBaseDaoJdbc(获取原始的JDBC Dao 层)

* (注意事项：-无)

* @return

* @exception

* @since 1.0.0

*/

public BaseDaoJdbc getBaseDaoJdbc (){

return baseDaoJdbc;

}

/**

*

* query(查询方法)

* (注意事项： – 目前只支持 Map List返回值)

* @param resultClass 返回类型如: Map.class

* @return

* @throws SQLException

* @exception

* @since 1.0.0

*/

public <E> E query (String sql,Class<E> resultClass,Object ... obj){

ResultSet rs = baseDaoJdbc.queryAll(sql, getConnection(), obj);

try {

if(resultClass == Map.class){

if(rs.next()) return (E) getResultMap(rs);

}else if(resultClass == List.class){

return (E) getResultList(rs);

}else{

throw new RuntimeException(""+resultClass +" 该类型目前还没有做扩展!");

}

} catch (SQLException e) {

logger.error(e.getMessage(),e);

}finally{

try {

baseDaoJdbc.closeAll(rs, rs.getStatement(), rs.getStatement().getConnection());

} catch (SQLException e) {

logger.error(e.getMessage(),e);

}

if(logger.isInfoEnabled())logger.info("关闭数据库连接!");

}

return null;

}

/**

*

* executeUpdate(增加、修改、删除操作)

* (注意事项：无)

* @param sql

* @param obj

* @return

* @exception

* @since 1.0.0

*/

public int executeUpdate(String sql,Object ...obj){

int k = 0;

k = getBaseDaoJdbc().executeUpdate(sql, getConnection(), obj);

return k;

}

/*

* 解析ResultSet 表列数据

*/

private Map<String,Object> getResultMap(ResultSet rs) throws SQLException{

Map<String, Object> rawMap = new HashMap<String, Object>();

ResultSetMetaData rsmd = rs.getMetaData(); // 表对象信息

int count = rsmd.getColumnCount(); // 列数

// 遍历之前需要调用 next()方法

for (int i = 1; i <= count; i++) {

String key = rsmd.getColumnLabel(i);

Object value = rs.getObject(key);

rawMap.put(key, value);

}

return rawMap;

}

/*

* 解析ResultSet 表数据

*/

private List<Map<String,Object>> getResultList(ResultSet rs) throws SQLException{

List<Map<String,Object>> rawList = new ArrayList<Map<String,Object>>();

while(rs.next()){

Map<String, Object> rawMap = getResultMap(rs);

rawList.add(rawMap);

}

return rawList;

}

3. [代码]BaseDaoJdbc

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public interface BaseDaoJdbc {

/**

* 关闭所有连接

* @param conn

* @param stmt

* @param rst

* @return

*/

public boolean closeAll(ResultSet rst,Statement stmt , Connection conn);

/**

* 关闭连接对象

* @param conn

* @return

*/

public boolean closeConnection(Connection conn);

/**

* 关闭执行sql对象

* @param stmt

* @return

*/

public boolean closeStatement(Statement stmt);

/**

* 关闭结果集

* @param rst

* @return

*/

public boolean closeResultSet(ResultSet rst);

/**

* 增删改

* @param sql

* @param conn

* @param obj

* @return

*/

public int executeUpdate(String sql,Connection conn,Object...obj);

/**

* 查询所有

* @param sql

* @param conn

* @param obj

* @return

*/

public ResultSet queryAll(String sql,Connection conn, Object... obj);

}

4. [代码]BaseDaoJdbcImpl

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public class BaseDaoJdbcimpl implements BaseDaoJdbc {

public boolean closeAll(ResultSet rst,Statement stmt , Connection conn) {

// TODO 关闭所有连接

boolean flag = false;

try {

if(rst!=null){

rst.close();

}

if(stmt!=null){

stmt.close();

}

if(conn!=null&&!conn.isClosed()){

conn.close();

flag = true;

}

} catch (SQLException e) {

e.printStackTrace();

}

return flag;

}

public boolean closeConnection(Connection conn) {

// TODO 关闭Connection对象

try {

if(conn!=null&&!conn.isClosed()){

try {

conn.close();

return true;

} catch (SQLException e) {

e.printStackTrace();

}

} catch (SQLException e) {

e.printStackTrace();

}

return false;

}

public boolean closeResultSet(ResultSet rst) {

// TODO 关闭ResultSet对象

if(rst!=null){

try {

rst.close();

return true;

} catch (SQLException e) {

e.printStackTrace();

}

return false;

}

public boolean closeStatement(Statement stmt) {

// TODO 关闭Statement 对象

if(stmt!=null){

if(stmt instanceof PreparedStatement){

try {

((PreparedStatement) stmt).close();

} catch (SQLException e) {

e.printStackTrace();

}

return false;

}

/**

* 增删改

* @param sql

* @param obj

* @return

*/

public int executeUpdate(String sql,Connection conn,Object...obj){

int i = 0 ;

PreparedStatement psts = null ;

try {

psts = conn.prepareStatement(sql) ;

if(obj!=null && obj.length>0){

for(int j=0;j<obj.length;j++){

psts.setObject((j+1), obj[j]) ;

}

i = psts.executeUpdate() ;

} catch (SQLException e) {

e.printStackTrace();

}finally{

closeAll(null, psts, conn);

}

return i ;

}

/**

* 查询所有

* @param sql

* @param obj

* @return ResultSet

*/

public ResultSet queryAll(String sql,Connection conn, Object... obj) {

PreparedStatement psts = null ;

ResultSet rs = null ;

try {

psts = conn.prepareStatement(sql) ;

if(obj!=null && obj.length>0){

for(int j=0;j<obj.length;j++){

psts.setObject((j+1), obj[j]) ;

}

rs = psts.executeQuery() ;

} catch (SQLException e) {

e.printStackTrace();

}

return rs ;

}

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