本套代码实现功能如下：
1.请求路由功能
2.Bean注入
3.执行匿名及命名参数sql语句
package com.hongyuan.core;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@SuppressWarnings("serial")
public class WebServlet extends HttpServlet {
protected HttpServletRequest request;
protected HttpServletResponse response;
protected Map<String,String> cfgParams=new HashMap<String,String>();
protected Map<String,String> dbSqls=new HashMap<String,String>();
protected Map<String,String> msgs=new HashMap<String,String>();
public void init(){}
@Override
public final void init(ServletConfig config) throws ServletException {
@SuppressWarnings("unchecked")
Enumeration<String> names = config.getInitParameterNames();
while(names.hasMoreElements()){
String name=names.nextElement();
if(name.startsWith("Bean_")){
//为servlet注入Bean对象
String beanName=name.substring("Bean_".length());
String beanClass=config.getInitParameter(name);
try {
Object bean = Class.forName(beanClass).newInstance();
bean.getClass().getMethod("setServlet",new Class[]{WebServlet.class}).invoke(bean,this);
this.getClass().getField(beanName).set(this,bean);
} catch (Exception e) {
e.printStackTrace();
}
}else if(name.startsWith("Sql_")){
String sqlName=name.substring("Sql_".length());
String sql=config.getInitParameter(name);
dbSqls.put(sqlName,sql);
}else if(name.startsWith("Message_")){
String msgName=name.substring("Message_".length());
String msg=config.getInitParameter(name);
msgs.put(msgName,msg);
}else if(name.startsWith("Param_")){
String paramName=name.substring("Param_".length());
String paramVal=config.getInitParameter(name);
cfgParams.put(paramName,paramVal);
}
}
}
@Override
public final void service(HttpServletRequest request, HttpServletResponse response){
this.request=request;
this.response=response;
try {
//根据路由参数将请求转交到指定方法执行
String routeParam=cfgParams.get("routeParam");
String action=this.get((routeParam==null||"".equals(routeParam))?"action":routeParam,"init");
Method method=this.getClass().getMethod(action);
method.invoke(this);
} catch (Exception e) {
this.init();
}
}
/**
* 展示指定页面
* @param page
*/
protected void show(String page){
try {
String pagePath=cfgParams.get("pagePath");
request.getRequestDispatcher(((pagePath==null||"".equals(pagePath))?"/WEB-INF/pages/":pagePath)+page).forward(request,response);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取指定名称的请求参数
* @param name
* @param def
* @return
*/
protected String get(String name,String def){
String value=request.getParameter(name);
if(value!=null&&!"".equals(value.trim())){
return value;
}else{
return def;
}
}
/**
* 向页面输出指定参数
* @param name
* @param value
*/
protected void put(String name,Object value){
request.setAttribute(name,value);
}
/**
* 获取指定名称的消息内容（可设置默认值）
* @param name
* @param def
* @return
*/
protected String getMsg(String name,String def){
String msg=msgs.get(name);
if(msg!=null&&!"".equals(msg.trim())){
return msg;
}else{
return def;
}
}
/**
* 获取指定名称的消息内容
* @param name
* @param def
* @return
*/
protected String getMsg(String name){
return this.getMsg(name,"");
}
}
package com.hongyuan.core;
public class WebBean {
protected DBUtil dbUtil=new DBUtil();
private WebServlet servlet;
public WebServlet getServlet() {
return servlet;
}
public void setServlet(WebServlet servlet) {
this.servlet = servlet;
}
public String getSql(String sqlName){
return servlet.dbSqls.get(sqlName);
}
}
package com.hongyuan.core;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.sql.DataSource;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
public class DBUtil {
private static DataSource dataSource = null;
static{
/**
* 初始化数据源，不同的数据库获取数据源的方式不同，可参考相应数据库的说明文档。
*/
MysqlDataSource mds=new MysqlDataSource();
mds.setURL("jdbc:mysql://localhost:3306/test");
mds.setUser("root");
mds.setPassword("123456");
dataSource=mds;
}
/**
* 获取数据库连接
* @return
* @throws SQLException
*/
public static Connection getConnection() throws SQLException {
return dataSource.getConnection();
}
/**
* 关闭数据库连接资源
* @param conn
* @param s
* @param rs
* @throws SQLException
*/
public static void close(Connection conn, Statement s, ResultSet rs) throws SQLException {
if (rs != null) rs.close();
if (s != null) s.close();
if (conn != null) conn.close();
}
/**
* 执行数据库查询语句
* @param sql 查询sql,匿名参数用？表示，命名参数使用“：参数名”表示
* @param params 查询参数
* @return
* @throws SQLException
*/
@SuppressWarnings("unchecked")
public List<Map<String,Object>> select(String sql,Object... params) throws SQLException{
return (List<Map<String,Object>>)this.executeSql(sql,params);
}
/**
* 执行数据库记录变更语句（增，删，改）
* @param sql 查询sql,匿名参数用？表示，命名参数使用“：参数名”表示
* @param params 查询参数
* @return
* @throws SQLException
*/
public int update(String sql,Object... params) throws SQLException{
return (Integer)this.executeSql(sql,params);
}
/**
* 通用Sql执行方法
* @param sql 查询sql,匿名参数用？表示，命名参数使用“：参数名”表示
* @param params 命名参数
* @return
* @throws SQLException
*/
public Object executeSql(String sql, Object... params) throws SQLException {
//处理命名参数
if(params!=null&¶ms[0] instanceof Map){
List<Object> pList=new ArrayList<Object>();
Map<String,Object> pMap=(Map<String, Object>)params[0];
Matcher pMatcher = Pattern.compile(":(\\w+)").matcher(sql);
while(pMatcher.find()){
String pName=pMatcher.group(1);
pList.add(pMap.get(pName));
}
sql=pMatcher.replaceAll("?");
params=pList.toArray();
}
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = DBUtil.getConnection();
ps = conn.prepareStatement(sql);
if (null != params) {
//初始化查询参数
for(int i=0;i<params.length;i++){
Object param = params[i];
if(param!=null){
ps.setObject(i+1,param);
}else{
ps.setNull(i+1,Types.NULL);
}
}
}
//处理结果集
boolean isResultSet = ps.execute();
List<Object> result = new ArrayList<Object>();
do {
if (isResultSet) {
List<Map<String,Object>> tableData=new ArrayList<Map<String,Object>>();
ResultSet resultSet=ps.getResultSet();
while(resultSet.next()){
Map<String,Object> rowData=new HashMap<String,Object>();
for(int i=1;i<=resultSet.getMetaData().getColumnCount();i++){
rowData.put(resultSet.getMetaData().getColumnName(i),resultSet.getObject(i));
}
tableData.add(rowData);
}
result.add(tableData);
} else {
result.add(new Integer(ps.getUpdateCount()));
}
} while ((isResultSet = ps.getMoreResults()) == true || ps.getUpdateCount() != -1);
//处理返回结果
if (result.size() == 0) {
return null;
} else if (result.size() == 1) {
return result.get(0);
} else {
return result;
}
} catch (SQLException e) {
throw new SQLException("无法执行的sql语句!");
} finally {
DBUtil.close(conn, ps, rs);
}
}
}
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app [
<!ENTITY webServlet SYSTEM "web-servlets.part">
<!ENTITY webServletMapping SYSTEM "web-servlet-mapping.part">
]>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
&webServlet;
&webServletMapping;
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
<servlet> <servlet-name>SimpleServlet</servlet-name> <servlet-class>com.hongyuan.test.SimpleServlet</servlet-class> <!-- 为servlet注入Bean实例 --> <init-param> <param-name>Bean_simpleBean</param-name> <param-value>com.hongyuan.test.SimpleBean</param-value> </init-param> <!-- sql语句，匿名参数 --> <init-param> <param-name>Sql_queryUserById</param-name> <param-value>select * from user where id=?</param-value> </init-param> <!-- sql语句，命名参数 --> <init-param> <param-name>Sql_queryUserByUserId</param-name> <param-value>select * from user where user_id=:userId</param-value> </init-param> <init-param> <param-name>Message_hello</param-name> <param-value>Hello Servlet!!!!</param-value> </init-param> <init-param> <param-name>Param_config</param-name> <param-value>this is a config param.</param-value> </init-param> </servlet>