Merge pull request YaleGuo#15 from YaleGuo/jdbc

JdbcTemplate implemented and single connection datasource supported.
ybqdren · Jun 20, 2020 · 7b819a7 · 7b819a7
2 parents 6b31c91 + a0b2f83
commit 7b819a7
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diff --git a/README.md b/README.md
@@ -7,3 +7,5 @@ IoC is the core of Minis. We will use a bean factory to manage all required bean
 mvc,integrate with IoC. mapping request uri to controller method,
 use handleadapter to invocate method and process response,
 and use view resolver to render return message (JSP). 
+
+Use jdbctemplate to access database, and connectionpool supported.
diff --git a/docs/readme.txt b/docs/readme.txt
@@ -1365,7 +1365,7 @@ URL通过映射机制找到实际的业务逻辑方法。
 		mv = ha.handle(processedRequest, response, handlerMethod);
 		render(processedRequest, response, mv);
 
-	render的实现，就是先按照规则找到具体的view(某个jsp页面)，拿到model数据，然后再render：
+	render的实现，就是先按照规则找到具体的view(某个jdp页面)，拿到model数据，然后再render：	
 	protected void render( HttpServletRequest request, HttpServletResponse response,ModelAndView mv) throws Exception {
 		String sTarget = mv.getViewName();
 		Map<String, Object> modelMap = mv.getModel();
@@ -1399,4 +1399,195 @@ URL通过映射机制找到实际的业务逻辑方法。
     	<bean id="logBeanPostProcessor" class="com.test.LogBeanPostProcessor" />
     名字不重要，是通过类型匹配进行注入的。
 
-    至此，有了完整的MVC实现。
+    至此，有了完整的MVC实现。
+
+
+
+-----------------------------------JDBC--------------------------------------
+1.
+	提供一个JdbcTemplate抽象类，实现基本JDBC的访问框架代码：
+	现在只实现数据查询。
+	public Object query(String sql) {
+		Connection con = null;
+		PreparedStatement stmt = null;
+		ResultSet rs = null;
+		Object rtnObj = null;
+
+			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+			con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databasename=DEMO;user=sa;password=Sql2016;");
+
+			stmt = con.prepareStatement(sql);
+			rs = stmt.executeQuery();
+
+			rtnObj = doInStatement(rs);
+
+		return rtnObj;
+	}
+
+	真正的业务代码留给用户自己实现doInStatement(),如实现User类：
+	public class UserJdbcImpl extends JdbcTemplate {
+	@Override
+	protected Object doInStatement(ResultSet rs) {
+		User rtnUser = null;
+			if (rs.next()) {
+				rtnUser = new User();
+				rtnUser.setId(rs.getInt("id"));
+				rtnUser.setName(rs.getString("name"));
+				rtnUser.setBirthday(new java.util.Date(rs.getDate("birthday").getTime()));
+			}
+
+		return rtnUser;
+	}
+
+	原有的UserService改成：
+	public class UserService {
+		public User getUserInfo(int userid) {
+			String sql = "select id, name,birthday from users where id="+userid;
+			JdbcTemplate jdbcTemplate = new UserJdbcImpl();
+			User rtnUser = (User)jdbcTemplate.query(sql);
+
+			return rtnUser;
+		}
+	}
+
+	这一步仅仅只做到了把JDBC查询语句中的格式化的语句抽离出来，让应用程序员只需要管sql语句并返回数据对象。
+
+
+
+
+2.
+	为了不让每个实体类都对应一个UserJdbcImpl类，写成callback模式，让用户自己动态写入：
+	public Object query(StatementCallback stmtcallback) {
+		Connection con = null;
+		Statement stmt = null;
+
+			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+			con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databasename=DEMO;user=sa;password=Sql2016;");
+
+			stmt = con.createStatement();
+
+			return stmtcallback.doInStatement(stmt);
+	}
+
+	同时支持PreparedStatement：
+	public Object query(String sql, Object[] args, PreparedStatementCallback pstmtcallback) {
+		Connection con = null;
+		PreparedStatement pstmt = null;
+
+			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+			con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databasename=DEMO;user=sa;password=Sql2016;");
+
+			pstmt = con.prepareStatement(sql);
+			if (args != null) {
+				for (int i = 0; i < args.length; i++) {
+					Object arg = args[i];
+					if (arg instanceof String) {
+						pstmt.setString(i+1, (String)arg);
+					}
+					else if (arg instanceof Integer) {
+						pstmt.setInt(i+1, (int)arg);
+					}
+					else if (arg instanceof java.util.Date) {
+						pstmt.setDate(i+1, new java.sql.Date(((java.util.Date)arg).getTime()));
+
+					}
+				}
+			}
+
+			return pstmtcallback.doInPreparedStatement(pstmt);
+	}
+
+	两个Callback接口如下：
+	public interface StatementCallback {
+		Object doInStatement(Statement stmt) throws SQLException;
+	}
+	public interface PreparedStatementCallback {
+		Object doInPreparedStatement(PreparedStatement stmt) throws SQLException;
+	}
+
+	这样应用程序员就只需要用一个JdbcTemplate类就可以了，不用为每一个业务类单独再做一个.
+
+	用户类改成使用Callback动态匿名类：
+	public User getUserInfo(int userid) {
+		final String sql = "select id, name,birthday from users where id=?";
+		return (User)jdbcTemplate.query(sql, new Object[]{new Integer(userid)},
+				(pstmt)->{			
+					ResultSet rs = pstmt.executeQuery();
+					User rtnUser = null;
+					if (rs.next()) {
+						rtnUser = new User();
+						rtnUser.setId(userid);
+						rtnUser.setName(rs.getString("name"));
+						rtnUser.setBirthday(new java.util.Date(rs.getDate("birthday").getTime()));
+					} else {
+					}
+					return rtnUser;
+				}
+		);
+	}
+
+	由于只需要一个JdbcTemplate，我们就可以事先在IoC容器中声明这个bean，然后自动注入进来。
+	<bean id="userService" class="com.test.service.UserService" /> 
+	<bean id="jdbcTemplate" class="com.minis.jdbc.core.JdbcTemplate" /> 
+
+	public class UserService {
+		@Autowired
+		JdbcTemplate jdbcTemplate;
+	}
+	这里采用的是按照名字匹配注入。
+
+	controller再注入service：
+	public class HelloWorldBean {
+		@Autowired
+		UserService userService;
+
+		@RequestMapping("/test8")
+		@ResponseBody
+		public User doTest8(HttpServletRequest request, HttpServletResponse response) {
+			int userid = Integer.parseInt(request.getParameter("id"));
+			User user = userService.getUserInfo(userid);		
+			return user;
+		}	
+	}
+
+
+3.
+	我们看到，JdbcTemplate中获取数据库连接信息仍然是hard coded：
+			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+			con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databasename=DEMO;user=sa;password=Sql2016;");
+	我们把这一部分代码包装成DataSource：
+			con = dataSource.getConnection();
+
+	并通过属性注入：
+	public class JdbcTemplate {
+		private DataSource dataSource;
+	}
+
+	配置文件：
+	<bean id="dataSource" class="com.minis.jdbc.datasource.SingleConnectionDataSource">
+	<property type="String" name="driverClassName" value="com.microsoft.sqlserver.jdbc.SQLServerDriver"/>
+	<property type="String" name="url" value="jdbc:sqlserver://localhost:1433;databasename=DEMO;"/>
+	<property type="String" name="username" value="sa"/>
+	<property type="String" name="password" value="Sql2016"/>
+    </bean>
+
+	<bean id="jdbcTemplate" class="com.minis.jdbc.core.JdbcTemplate" >
+	<property type="javax.sql.DataSource" name="dataSource" ref="dataSource"/>
+	</bean> 
+
+	DataSource定义如下：
+	public class SingleConnectionDataSource implements DataSource {
+		private String driverClassName;
+		private String url;
+		private String username;
+		private String password;
+		private Properties connectionProperties;	
+		private Connection connection;
+
+		@Override
+		public Connection getConnection() throws SQLException {
+			return getConnectionFromDriver(getUsername(), getPassword());
+		}
+	}
+
+	这样在bean初始化的时候，就生成了一个数据库连接，然后注入JdbcTemplate来使用。
diff --git a/resources/applicationContext.xml b/resources/applicationContext.xml
@@ -11,6 +11,20 @@
         <property type="com.test.service.BaseService" name="ref1" ref="baseservice"/>
 	</bean>
 	<bean id="baseservice" class="com.test.service.BaseService" /> 
+	<bean id="userService" class="com.test.service.UserService" /> 
+
+	<bean id="dataSource" class="com.minis.jdbc.datasource.SingleConnectionDataSource">
+	<property type="String" name="driverClassName" value="com.microsoft.sqlserver.jdbc.SQLServerDriver"/>
+	<property type="String" name="url" value="jdbc:sqlserver://localhost:1433;databasename=DEMO;"/>
+	<property type="String" name="username" value="sa"/>
+	<property type="String" name="password" value="Sql2016"/>
+    </bean>
+
+
+	<bean id="jdbcTemplate" class="com.minis.jdbc.core.JdbcTemplate" >
+	<property type="javax.sql.DataSource" name="dataSource" ref="dataSource"/>
+	</bean> 
+
 
 	<bean id="contextListener" class="com.test.MyListener" /> 
 

diff --git a/src/com/minis/jdbc/core/JdbcTemplate.java b/src/com/minis/jdbc/core/JdbcTemplate.java
@@ -0,0 +1,93 @@
+package com.minis.jdbc.core;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.Statement;
+import javax.sql.DataSource;
+
+
+
+public class JdbcTemplate {
+	private DataSource dataSource;
+
+	public void setDataSource(DataSource dataSource) {
+		this.dataSource = dataSource;
+	}
+
+	public DataSource getDataSource() {
+		return this.dataSource;
+	}
+
+	public JdbcTemplate() {
+	}
+
+	public Object query(StatementCallback stmtcallback) {
+		Connection con = null;
+		Statement stmt = null;
+
+		try {
+			con = dataSource.getConnection();
+
+			stmt = con.createStatement();
+
+			return stmtcallback.doInStatement(stmt);
+		}
+		catch (Exception e) {
+				e.printStackTrace();
+		}
+		finally {
+			try {
+				stmt.close();
+				con.close();
+			} catch (Exception e) {
+
+			}
+		}
+
+		return null;
+
+	}
+	public Object query(String sql, Object[] args, PreparedStatementCallback pstmtcallback) {
+		Connection con = null;
+		PreparedStatement pstmt = null;
+
+		try {
+			con = dataSource.getConnection();
+
+			pstmt = con.prepareStatement(sql);
+			if (args != null) {
+				for (int i = 0; i < args.length; i++) {
+					Object arg = args[i];
+					if (arg instanceof String) {
+						pstmt.setString(i+1, (String)arg);
+					}
+					else if (arg instanceof Integer) {
+						pstmt.setInt(i+1, (int)arg);
+					}
+					else if (arg instanceof java.util.Date) {
+						pstmt.setDate(i+1, new java.sql.Date(((java.util.Date)arg).getTime()));
+
+					}
+				}
+			}
+
+
+			return pstmtcallback.doInPreparedStatement(pstmt);
+		}
+		catch (Exception e) {
+				e.printStackTrace();
+		}
+		finally {
+			try {
+				pstmt.close();
+				con.close();
+			} catch (Exception e) {
+
+			}
+		}
+
+		return null;
+
+	}
+}
diff --git a/src/com/minis/jdbc/core/OldJdbcTemplate.java b/src/com/minis/jdbc/core/OldJdbcTemplate.java
@@ -0,0 +1,45 @@
+package com.minis.jdbc.core;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+
+
+public abstract class OldJdbcTemplate {
+	public OldJdbcTemplate() {
+	}
+
+	public Object query(String sql) {
+		Connection con = null;
+		PreparedStatement stmt = null;
+		ResultSet rs = null;
+		Object rtnObj = null;
+
+		try {
+			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+			con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databasename=DEMO;user=sa;password=Sql2016;");
+
+			stmt = con.prepareStatement(sql);
+			rs = stmt.executeQuery();
+
+			rtnObj = doInStatement(rs);
+		}
+		catch (Exception e) {
+				e.printStackTrace();
+		}
+		finally {
+			try {
+				rs.close();
+				stmt.close();
+				con.close();
+			} catch (Exception e) {
+
+			}
+		}
+
+		return rtnObj;
+
+	}
+	protected abstract  Object doInStatement(ResultSet rs);
+}
diff --git a/src/com/minis/jdbc/core/PreparedStatementCallback.java b/src/com/minis/jdbc/core/PreparedStatementCallback.java
@@ -0,0 +1,8 @@
+package com.minis.jdbc.core;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+public interface PreparedStatementCallback {
+	Object doInPreparedStatement(PreparedStatement stmt) throws SQLException;
+}
diff --git a/src/com/minis/jdbc/core/StatementCallback.java b/src/com/minis/jdbc/core/StatementCallback.java
@@ -0,0 +1,8 @@
+package com.minis.jdbc.core;
+
+import java.sql.SQLException;
+import java.sql.Statement;
+
+public interface StatementCallback {
+	Object doInStatement(Statement stmt) throws SQLException;
+}