前序文章：
IDEA(2020版)实现Servlet程序 – 每天进步一点点
IDEA(2020版)实现Servlet的生命周期 – 每天进步一点点
IDEA(2020版)实现ServletConfig和ServletContext – 每天进步一点点
本文主要介绍在IDEA中实现HttpServletResponse对象
本节源代码：https://box356.lanzoub.com/ioORx2rv2f4h
1.发送响应消息体相关方法
右击src，选择New—>Create New Servlet
名称定为TestServlet4_10，代码参考如下：
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 java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
@WebServlet(name = "TestServlet4_10",value = "/test410")
public class TestServlet4_10 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
String data = "itcast";
// 获取字节输出流对象
OutputStream out = response.getOutputStream();
out.write(data.getBytes());// 输出字节信息
System.out.println(data.getBytes());
// 获取字符输出流对象
PrintWriter print = response.getWriter();
print.write(data); // 输出信息
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
doGet(request, response);
}
}
创建之后是这样：
在浏览器里输入
http://localhost:8080/Servlet01_war_exploded/test410效果如下：
2.实现重定向
大概逻辑，编写两个网页login.html和welcome.html，然后编写一个登录接口，如果登录成功跳转到welcome.html
右击 web—>New—>HTML file，名称暂定为login
代码参考如下：
(请注意代码中 action的地址 这是请求后台的地址，要和servlet对应上)
<!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>
<form action="/chapter04/LoginServlet" method="post">
用户名： <input type="text" name="username" /><br />
密 码：<input type="password" name="password"/><br />
<input type="submit" value="登录" />
</form>
</body>
</html>
再创建一个welcome.html，代码参考如下：
<!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>
欢迎你，登录成功！
</body>
</html>
然后再右击src—>New—>Create New Servlet，名字就为 LoginServlet
代码参考如下：
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 java.io.IOException;
@WebServlet(name = "LoginServlet",value = "/LoginServlet")
public class LoginServlet extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
// 用HttpServletRequest对象的getParameter()方法获取用户名和密码
String username = request.getParameter("username");
String password = request.getParameter("password");
// 假设用户名和密码分别为：itcast和123
if ("itcast".equals(username) &&"123".equals(password)) {
// 如果用户名和密码正确，重定向到 welcome.html
response.sendRedirect("/Servlet01_war_exploded/welcome.html");
} else {
// 如果用户名和密码错误，重定向到login.html
response.sendRedirect("/Servlet01_war_exploded/login.html");
}
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
doGet(request, response);
}
}
我们在浏览器里输入下面的网址：
http://localhost:8080/Servlet01_war_exploded/login.html实习的效果如下：
3.解决中文乱码问题
实际上加上下面这行代码就搞定了。
response.setContentType("text/html;charset=utf-8");右击src—>New—>Create New Servlet，名字为TestServlet4_16
代码参考如下：
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 java.io.IOException;
import java.io.PrintWriter;
@WebServlet(name = "TestServlet4_16",value = "/test416")
public class TestServlet4_16 extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
//设置字符编码
response.setContentType("text/html;charset=utf-8");
String data = "中国";
PrintWriter out = response.getWriter();
out.println(data);
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)throws ServletException, IOException {
doGet(request, response);
}
}
在浏览器里输入下面的地址：
http://localhost:8080/Servlet01_war_exploded/test416实习效果如下：
