package helloworld;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
/**
*/
@WebServlet("/HelloWorld")
public class HelloWorld extends HttpServlet {
private static final long serialVersionUID = 1L;
private String diverClass;
private String userName;
private String password;
private String url;
/**
* Default constructor.
*/
public HelloWorld() {
// TODO Auto-generated constructor stub
}
public String resultSetToJson(ResultSet rs) throws SQLException,JSONException
{
// json数组
JSONArray array = new JSONArray();
// 获取列数
ResultSetMetaData metaData = rs.getMetaData();
int columnCount = metaData.getColumnCount();
// 遍历ResultSet中的每条数据
while (rs.next()) {
JSONObject jsonObj = new JSONObject();
// 遍历每一列
for (int i = 1; i <= columnCount; i++) {
String columnName =metaData.getColumnLabel(i);
String value = rs.getString(columnName);
jsonObj.put(columnName, value);
}
array.put(jsonObj);
}
return array.toString();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
response.setContentType("text/html");
response.setCharacterEncoding("gb2312");
PrintWriter out = response.getWriter();
diverClass = /* getServletConfig(). */getServletContext().getInitParameter("driver");
userName = /* getServletConfig(). */getServletContext().getInitParameter("username");
password = /* getServletConfig(). */getServletContext().getInitParameter("password");
url = /* getServletConfig(). */getServletContext().getInitParameter("url");
String sql = request.getParameter("sql");
if (sql==null){
sql="SELECT * FROM ANIMALS";
}
try {
Class.forName(diverClass);
//conn = DriverManager.getConnection("jdbc:mysql://localhost/bbs?user=root&password=12345678");
conn = DriverManager.getConnection(url, userName,password);
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
HelloWorld hello = new HelloWorld();
try {
String data = hello.resultSetToJson(rs);
out.println(data);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if(rs != null) {
rs.close();
rs = null;
}
if(stmt != null) {
stmt.close();
stmt= null;
}
if(conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("<div style='width:100px;height:100px;background-color:red'>123123</div>");
}
}
