23，24在天上和火车上，24晚上到家就去吃烧烤！零下42℃我也要去吃！
打开电脑，啥玩意
我好像很长时间之前重装了电脑，劳资的环境全都没了，写个毛线代码。
最令人开心的是，家里没网，只能蹭楼下wifi。
用了一天，装的差不多了
- jdk，jre 版本9.0.4
- tomcat 9.0.2
- eclipse jee oxygen（主要用java ee和java）
- navicat premium 12（破解的乱七八糟的）
- putty
- mysql 5.7
原来有的
- Xsell 5
- FlashFXP 5
连上服务器
弄好了tomcat上http跳转https，参考
http://blog.csdn.net/bao19901210/article/details/8768362
用yum装上了mysql服务，参考
http://www.linuxidc.com/Linux/2016-09/135288.htm
测试代码
emmm，傻敷敷的把整个项目包复制到/usr/local/apache-tomcat-9.0.2/webapps/ROOT/下，结果和之前的一样500，然后在问学姐的时候突然发现之前百度的war包发布的方式我放错了位置，重试一下
把项目在eclipse里export成war包，然后上传到服务器/usr/local/apache-tomcat-9.0.2/webapps/下，运行成功，放炮去了。
接下来是测试项目包cuz_welcome的文件：
- src/cuz_welcome/ConnectMysql.java
package cuz_welcome;
import java.sql.*;
import java.util.LinkedList;
public class ConnectMysql
{
// JDBC 驱动名及数据库 URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/studentdb";
// 数据库的用户名与密码，需要根据自己的设置
static final String USER = "root";
static final String PASS = "root";
public static String getStu()
{
// TODO Auto-generated constructor stub
Connection conn = null;
Statement stmt = null;
LinkedList<Student> list = new LinkedList<>();
try
{
// 注册 JDBC 驱动
Class.forName("com.mysql.jdbc.Driver");
// 打开链接
// System.out.println("连接数据库...");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
// 执行查询
// System.out.println(" 实例化Statement对...");
stmt = conn.createStatement();
String sql;
sql = "SELECT stuid, name, sex FROM t_student";
ResultSet rs = stmt.executeQuery(sql);
// 展开结果集数据库
while (rs.next())
{
// 通过字段检索
Student stu = new Student();
stu.stuId = rs.getInt("stuid");
stu.name = rs.getString("name");
stu.sex = rs.getString("sex");
list.add(stu);
// 输出数据
// System.out.print("ID: " + stu.stuId);
// System.out.print(", 姓名: " + stu.name);
// System.out.print(", 性别: " + stu.sex);
// System.out.print("\n");
}
// 完成后关闭
rs.close();
stmt.close();
conn.close();
}
catch (SQLException se)
{
// 处理 JDBC 错误
se.printStackTrace();
}
catch (Exception e)
{
// 处理 Class.forName 错误
e.printStackTrace();
}
finally
{
// 关闭资源
try
{
if (stmt != null)
stmt.close();
}
catch (SQLException se2)
{
} // 什么都不做
try
{
if (conn != null)
conn.close();
}
catch (SQLException se)
{
se.printStackTrace();
}
}
// System.out.println("Goodbye!");
return TestMapToJson.testMysqlToJson(list);
}
}
- src/cuz_welcome/Student.java
package cuz_welcome;
public class Student
{
int stuId;
String name;
String sex;
}
- src/cuz_welcome/estMapToJson.java
package cuz_welcome;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class TestMapToJson
{
public static void main(String[] args)
{
// TODO Auto-generated method stub
test();
}
public static void testMapToJSON(){
Map map1 = new HashMap();
map1.put( "name", "json" );
map1.put( "bool", Boolean.TRUE );
map1.put( "int", new Integer(1) );
map1.put( "arr", new String[]{"a","b"} );
map1.put( "func", "function(i){ return this.arr[i]; }" );
JSONObject jsonObject = JSONObject.fromObject( map1 );
Map map2 = new HashMap();
map2.put( "name", "json" );
map2.put( "bool", Boolean.TRUE );
map2.put( "int", new Integer(1) );
map2.put( "arr", new String[]{"a","b"} );
map2.put( "func", "function(i){ return this.arr[i]; }" );
jsonObject.fromObject(map2);
System.out.println( jsonObject );
}
public static void test()
{
LinkedList<JSONObject> li = new LinkedList<>();
for (int i = 0; i < 10; i++)
{
Student stu = new Student();
stu.stuId = 10001 + i;
stu.name = "aa";
stu.sex = "man";
Map map = new HashMap<>();
map.put( "stuId", new Integer(stu.stuId) );
map.put("name", stu.name);
map.put("sex", stu.sex);
JSONObject jsonObject = JSONObject.fromObject( map );
li.add(jsonObject);
}
JSONArray jsonArray = JSONArray.fromObject( li );
Map stuMap = new HashMap();
stuMap.put("students", jsonArray);
JSONObject stuJsonObject = JSONObject.fromObject( stuMap );
System.out.println( stuJsonObject );
}
public static String testMysqlToJson(LinkedList<Student> list)
{
LinkedList<JSONObject> li = new LinkedList<>();
for (int i = 0; i < list.size(); i++)
{
Student stu = new Student();
stu.stuId = list.get(i).stuId;
stu.name = list.get(i).name;
stu.sex = list.get(i).sex;
Map map = new HashMap<>();
map.put( "stuId", new Integer(stu.stuId) );
map.put("name", stu.name);
map.put("sex", stu.sex);
JSONObject jsonObject = JSONObject.fromObject( map );
li.add(jsonObject);
}
JSONArray jsonArray = JSONArray.fromObject( li );
Map stuMap = new HashMap();
stuMap.put("students", jsonArray);
JSONObject stuJsonObject = JSONObject.fromObject( stuMap );
System.out.println( stuJsonObject );
return stuJsonObject.toString();
}
}
- WebContent/testMysql.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@ page import= "cuz_welcome.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
</head>
<body>
<%=ConnectMysql.getStu()%>
</body>
</html>
- WebContent/testMysql2.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@ page import= "cuz_welcome.*"%>
<%@ page import="java.sql.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
</head>
<body>
<%
Connection con = null;
Statement st = null;
ResultSet rs = null;
try
{
Class.forName("com.mysql.jdbc.Driver");
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
try
{
con = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/studentdb?useUnicode=true&characterEncoding=UTF-8&useSSL=false", "root",
"root");
st = con.createStatement();
rs = st.executeQuery("select * from student");
out.print("<table border=1>");
out.print("<tr>");
out.print("<th>学号</th>");
out.print("<th>姓名</th>");
out.print("<th>性别</th>");
out.print("</tr>");
while (rs.next())
{
int stuId = rs.getInt(1);
String stuName = rs.getString(2);
String stuSex = rs.getString(3);
out.print("<tr>");
out.print("<td>" + stuId + "</td>");
out.print("<td>" + stuName + "</td>");
out.print("<td>" + stuSex + "</td>");
out.print("</tr>");
}
out.print("</table>");
}
catch (SQLException e)
{
e.printStackTrace();
}
finally
{
try
{
if (rs != null)
{
rs.close();
}
if (st != null)
{
st.close();
}
if (con != null)
{
con.close();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
}
%>
</body>
</html>
最后测试成功，两个jsp可以取到数据库的数据，然后在微信开发工具中测试，发现取到的是整个页面有head有body，并不是只有返回的json，所以微信小程序上显示失败。
结果
思路要重新整理，学姐说逻辑有很大问题，代码很乱，jsp 只负责通过 el 表达式、jstl 表达式、ognl 表达式 展示数据。
所以，理清思路，使用Servlet返回响应数据给客户端。
