我为部署在tomcat上的Java（.war）应用程序创建了index.html文件。
我已经有一个Java Servlet文件，该文件查询远程db服务器以获取我存储在其中的图片。
该Java Servlet文件称为ImageServlet.java。
我需要HTML页面来显示ImageServlet.java查询的图像。
我只是不知道在检索我的图片时如何引用servlet。
下面是ImageServlet文件：
package test;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.bind.DatatypeConverter;
public class ImageServlet extends HttpServlet
{
Connection con = null;
public Connection getConnection()
{
try {
Class.forName("com.mysql.jdbc.Driver");
String url = System.getenv("FUJI_MYSQL_URL");
return DriverManager.getConnection(url,
System.getenv("FUJI_MYSQL_USER"), System.getenv("FUJI_MYSQL_PASS"));
}
catch (Exception ex)
{
System.out.println(ex.getMessage());
}return null;
}
public static byte[] getImageById(Connection con)
{
String query = "select photo from photos where picid = 1";
try
{
PreparedStatement stmt = con.prepareStatement(query);
stmt.execute();
ResultSet resultSet = stmt.getResultSet();
resultSet.first();
Blob blob = resultSet.getBlob(1);
stmt.close();
con.close();
return blob.getBytes(1L, (int)blob.length());
} catch (Exception ex) {
System.out.println(ex.getMessage());
}return null;
}
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException
{
PrintWriter out = res.getWriter();
Connection con = null;
con = getConnection();
byte[] data = getImageById(con);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.write(data);
out.println("<!DOCTYPE html><html xmlns=\"http://www.w3.org/1999/xhtml\"><head><title>PI_SQLogo.png</title></head><body><img src='data:image/png;base64," + DatatypeConverter.printBase64Binary(baos.toByteArray()) + "'></body></html>");
out.close();
}
}
@WebServlet("/")
public class ImageServlet extends HttpServlet {
//...
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//...
byte[] data = getImageById(con);
response.setContentType("image/jpeg"); // Assuming your image is .jpg
response.setContentLength(data.length);
response.getOutputStream().write(data);
}
//..
}
然后输入index.html或index.jsp：
<img src="${pageContext.request.contextPath}/foo.jpg">