package hjp.smart4j.framework.helper; import hjp.smart4j.framework.util.CollectionUtil;
import hjp.smart4j.framework.util.PropsUtil;
import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory; import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties; /**
* 数据库操作助手类
*/
public class DatabaseHelper {
private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class); private static final ThreadLocal<Connection> CONNECTION_HOLDER;
private static final QueryRunner QUERY_RUNNER;
private static final BasicDataSource DATA_SOURCE; static {
CONNECTION_HOLDER = new ThreadLocal<Connection>();
QUERY_RUNNER = new QueryRunner();
DATA_SOURCE = new BasicDataSource(); Properties conf = PropsUtil.loadProps("config.properties");
String driver = conf.getProperty("jdbc.driver");
String url = conf.getProperty("jdbc.url");
String username = conf.getProperty("jdbc.username");
String password = conf.getProperty("jdbc.password");
DATA_SOURCE.setDriverClassName(driver);
DATA_SOURCE.setUrl(url);
DATA_SOURCE.setUsername(username);
DATA_SOURCE.setPassword(password); } /**
* 获取数据库连接
*/
public static Connection getConnection() {
Connection connection = CONNECTION_HOLDER.get();
if (connection == null) {
try {
connection = DATA_SOURCE.getConnection();
} catch (SQLException e) {
LOGGER.error("get connection failure", e);
throw new RuntimeException(e);
} finally {
CONNECTION_HOLDER.set(connection);
}
}
return connection;
} /**
* 查询实体列表
*/
public static <T> List<T> queryEntityList(Class<T> entityClass, String sql, Object... params) {
List<T> entityList;
try {
Connection conn = getConnection();
entityList = QUERY_RUNNER.query(conn, sql, new BeanListHandler<T>(entityClass), params);
} catch (SQLException e) {
LOGGER.error("query entity list failure", e);
throw new RuntimeException(e);
}
return entityList;
} /**
* 查询实体
*/
public static <T> T queryEntity(Class<T> entityClass, String sql, Object... params) {
T entity;
try {
Connection connection = getConnection();
entity = QUERY_RUNNER.query(connection, sql, new BeanHandler<T>(entityClass), params);
} catch (SQLException e) {
LOGGER.error("query entity failure", e);
throw new RuntimeException(e);
}
return entity;
} /**
* 执行查询语句
*/
public static List<Map<String, Object>> executeQuery(String sql, Object... params) {
List<Map<String, Object>> result;
try {
Connection connection = getConnection();
result = QUERY_RUNNER.query(connection, sql, new MapListHandler(), params);
} catch (Exception e) {
LOGGER.error("execute query failure", e);
throw new RuntimeException(e);
}
return result;
} /**
* 执行更新语句（update、insert、delete）
*/
public static int executeUpdate(String sql, Object... params) {
int rows = 0;
try {
Connection connection = getConnection();
rows = QUERY_RUNNER.update(connection, sql, params);
} catch (SQLException e) {
LOGGER.error("execute update failure", e);
throw new RuntimeException(e);
}
return rows;
} /**
* 插入实体
*/
public static <T> boolean insertEntity(Class<T> entityClass, Map<String, Object> fieldMap) {
if (CollectionUtil.isEmpty(fieldMap)) {
LOGGER.error("can not insert entity: fieldMap is empty");
return false;
} String sql = "insert into " + getTableName(entityClass);
StringBuilder columns = new StringBuilder(" (");
StringBuilder values = new StringBuilder(" (");
for (String fieldName : fieldMap.keySet()) {
columns.append(fieldName).append(", ");
values.append("?, ");
}
columns.replace(columns.lastIndexOf(", "), columns.length(), ") ");
values.replace(values.lastIndexOf(", "), values.length(), ") ");
sql += columns + " values " + values; Object[] params = fieldMap.values().toArray();
return executeUpdate(sql, params) == 1;
} /**
* 更新实体
*/
public static <T> boolean updateEntity(Class<T> entityClass, long id, Map<String, Object> fieldMap) {
if (CollectionUtil.isEmpty(fieldMap)) {
LOGGER.error("can not update entity: fieldMap is empty");
return false;
} String sql = "update " + getTableName(entityClass) + " set ";
StringBuilder columns = new StringBuilder();
for (String fieldName : fieldMap.keySet()) {
columns.append(fieldName).append("=?, ");
}
sql += columns.substring(0, columns.lastIndexOf(", ")) + " where id=?"; List<Object> paramList = new ArrayList<Object>();
paramList.addAll(fieldMap.values());
paramList.add(id);
Object[] params = paramList.toArray();
return executeUpdate(sql, params) == 1;
} /**
* 删除实体
*/
public static <T> boolean deleteEntity(Class<T> entityClass, long id) {
String sql = "delete from " + getTableName(entityClass) + " where id=?";
return executeUpdate(sql, id) == 1;
} /**
* 通过类名获取表名
*/
private static String getTableName(Class<?> entityClass) {
return entityClass.getSimpleName();
} /**
* 执行SQL文件
*/
public static void executeSqlFile(String filePath) {
InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
try {
String sql;
while ((sql = reader.readLine()) != null) {
executeUpdate(sql);
}
} catch (IOException e) {
LOGGER.error("execute sql file failure", e);
throw new RuntimeException(e);
}
} /**
* 开启事务
*/
public static void beginTransaction() {
Connection conn = getConnection();
if (conn != null) {
try {
conn.setAutoCommit(false);
} catch (SQLException e) {
LOGGER.error("begin transaction failure", e);
throw new RuntimeException(e);
} finally {
CONNECTION_HOLDER.set(conn);
}
}
} /**
* 提交事务
*/
public static void commitTransaction() {
Connection conn = getConnection();
if (conn != null) {
try {
conn.commit();
conn.close();
} catch (SQLException e) {
LOGGER.error("commit transaction failure", e);
throw new RuntimeException(e);
} finally {
CONNECTION_HOLDER.remove();
}
}
} /**
* 回滚事务
*/
public static void rollbackTransaction() {
Connection conn = getConnection();
if (conn != null) {
try {
conn.rollback();
conn.close();
} catch (SQLException e) {
LOGGER.error("rollback transaction failure", e);
throw new RuntimeException(e);
} finally {
CONNECTION_HOLDER.remove();
}
}
}
}
DatabaseHelper
需要关注的地方
1、ThreadLocal<Connection>
泛型内指定存储数据类型
2、数据库连接对象创建后不再关闭，交由BasicDataSource管理
3、java中泛型T和？
T用于指定参数类型或返回类型，泛型方法要在方法名前标记<T>
?用于泛型类型指定，如Class<?>，任意类型的Class类；List<?> list，任意类型集合