Javaweb - servlet中response响应字符、字节数据案例演示

Response响应字符数据

案例举例

运行测试 响应HTML标签案例

运行测试content简化（支持中文） Response响应字节数据

案例演示（响应图片）

运行测试 简化IO流传输

导入commons-io工具类运行测试

我们可以从响应、response对象调用字符流方法，获取字符，写入到response(响应)中

package com.taotao.web.Response;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet("/resp3")
public class ResponseDemo3 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取字符输出流
        PrintWriter writer = response.getWriter();
        writer.write("aaa");
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

package com.taotao.web.Response;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet("/resp3")
public class ResponseDemo3 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取字符输出流
        PrintWriter writer = response.getWriter();
        //content-type
        response.setHeader("content-type","text/html");
        writer.write("aaa");
        writer.write("this was response write h1 content");
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

同样我们可以通过IO流响应字节流文件，比如图片 - 提取图片 - 获得response对象的字节输出流，然后持续输送字节数据即可，下面是IO流内容

package com.taotao.web.Response;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;



@WebServlet("/resp4")
@SuppressWarnings({"all"})
public class ResponseDemo4 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.读取文件
        FileInputStream fis = new FileInputStream("d://zhong.jpg");

        //2.获取response字节输出流
        ServletOutputStream os = response.getOutputStream();

        //3.完成流的copy
        byte[] buf = new byte[1024];
        int len = 0;
        while((len = fis.read(buf)) != -1){
            os.write(buf,0,len);
        }

        fis.close();
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

编写pom.xml文件，导入工具类

        
            commons-io
            commons-io
            2.6
        

刷新导入

重新写IO传输内容

package com.taotao.web.Response;

import org.apache.commons.io.IOUtils;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;



@WebServlet("/resp4")
@SuppressWarnings({"all"})
public class ResponseDemo4 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.读取文件
        FileInputStream fis = new FileInputStream("d://zhong.jpg");

        //2.获取response字节输出流
        ServletOutputStream os = response.getOutputStream();

        //3.完成流的copy
        IOUtils.copy(fis,os);

        fis.close();
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}