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Java Jquery和servlet与ajax的通信

java javascript jquery ajax servlets

Java Jquery和servlet与ajax的通信,java,javascript,jquery,ajax,servlets,Java,Javascript,Jquery,Ajax,Servlets,我想在tomcat中的Jquery函数和servlet之间建立通信 Servlet代码： import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.PrintWriter; import javax.servlet.ServletExcept

我想在tomcat中的Jquery函数和servlet之间建立通信

Servlet代码：

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



public class Test extends HttpServlet {
public static String getBody(HttpServletRequest request) throws IOException {

    String body = null;
    StringBuilder stringBuilder = new StringBuilder();
    BufferedReader bufferedReader = null;

    try {
        InputStream inputStream = request.getInputStream();
        if (inputStream != null) {
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            char[] charBuffer = new char[128];
            int bytesRead = -1;
            while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                stringBuilder.append(charBuffer, 0, bytesRead);
            }
        } else {
            stringBuilder.append("");
        }
    } catch (IOException ex) {
        throw ex;
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException ex) {
                throw ex;
            }
        }
    }
    body = stringBuilder.toString();
    return body;
}
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        System.out.println(getBody(request));
        out.println("Success Call Ajax POST");

      }
    public void doGet( HttpServletRequest request, HttpServletResponse
        response ) throws ServletException, IOException{
    response.setContentType("text/html");
    response.setCharacterEncoding( "UTF-8" );
    PrintWriter out = response.getWriter();
    out.println("Get Method");

  }

}

<?xml version="1.0" encoding="UTF-8"?>
<web-app
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
  <servlet>
    <servlet-name>Test</servlet-name>
    <servlet-class>com.servlets.Test</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Test</servlet-name>
    <url-pattern>/toto</url-pattern>
  </servlet-mapping>
</web-app>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
    function login(){  

      $.ajax({  
        type: "POST",  
        url: "http://localhost:8080/test/toto",  
        data: "POST Call",
        success: function(result){  
          alert("success call"+result);
        },
        error: function(XMLHttpRequest, textStatus, errorThrown) { 
            alert("Status: " + textStatus); alert("Error: " + errorThrown); 
        }                 
      });  
    }        
    </script>
    <title>My AJAX</title>
</head>
<body>
    <button type="button" onclick="login()">Click Me!</button>
</body>
servlet标识在web.xml中定义

web.xml:

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



public class Test extends HttpServlet {
public static String getBody(HttpServletRequest request) throws IOException {

    String body = null;
    StringBuilder stringBuilder = new StringBuilder();
    BufferedReader bufferedReader = null;

    try {
        InputStream inputStream = request.getInputStream();
        if (inputStream != null) {
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            char[] charBuffer = new char[128];
            int bytesRead = -1;
            while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                stringBuilder.append(charBuffer, 0, bytesRead);
            }
        } else {
            stringBuilder.append("");
        }
    } catch (IOException ex) {
        throw ex;
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException ex) {
                throw ex;
            }
        }
    }
    body = stringBuilder.toString();
    return body;
}
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        System.out.println(getBody(request));
        out.println("Success Call Ajax POST");

      }
    public void doGet( HttpServletRequest request, HttpServletResponse
        response ) throws ServletException, IOException{
    response.setContentType("text/html");
    response.setCharacterEncoding( "UTF-8" );
    PrintWriter out = response.getWriter();
    out.println("Get Method");

  }

}

<?xml version="1.0" encoding="UTF-8"?>
<web-app
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
  <servlet>
    <servlet-name>Test</servlet-name>
    <servlet-class>com.servlets.Test</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Test</servlet-name>
    <url-pattern>/toto</url-pattern>
  </servlet-mapping>
</web-app>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
    function login(){  

      $.ajax({  
        type: "POST",  
        url: "http://localhost:8080/test/toto",  
        data: "POST Call",
        success: function(result){  
          alert("success call"+result);
        },
        error: function(XMLHttpRequest, textStatus, errorThrown) { 
            alert("Status: " + textStatus); alert("Error: " + errorThrown); 
        }                 
      });  
    }        
    </script>
    <title>My AJAX</title>
</head>
<body>
    <button type="button" onclick="login()">Click Me!</button>
</body>


试验
com.servlets.Test
试验
/托托
以下HTML包含JQuery函数：

Jquery代码：

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



public class Test extends HttpServlet {
public static String getBody(HttpServletRequest request) throws IOException {

    String body = null;
    StringBuilder stringBuilder = new StringBuilder();
    BufferedReader bufferedReader = null;

    try {
        InputStream inputStream = request.getInputStream();
        if (inputStream != null) {
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            char[] charBuffer = new char[128];
            int bytesRead = -1;
            while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                stringBuilder.append(charBuffer, 0, bytesRead);
            }
        } else {
            stringBuilder.append("");
        }
    } catch (IOException ex) {
        throw ex;
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException ex) {
                throw ex;
            }
        }
    }
    body = stringBuilder.toString();
    return body;
}
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        System.out.println(getBody(request));
        out.println("Success Call Ajax POST");

      }
    public void doGet( HttpServletRequest request, HttpServletResponse
        response ) throws ServletException, IOException{
    response.setContentType("text/html");
    response.setCharacterEncoding( "UTF-8" );
    PrintWriter out = response.getWriter();
    out.println("Get Method");

  }

}

<?xml version="1.0" encoding="UTF-8"?>
<web-app
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
  <servlet>
    <servlet-name>Test</servlet-name>
    <servlet-class>com.servlets.Test</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Test</servlet-name>
    <url-pattern>/toto</url-pattern>
  </servlet-mapping>
</web-app>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
    function login(){  

      $.ajax({  
        type: "POST",  
        url: "http://localhost:8080/test/toto",  
        data: "POST Call",
        success: function(result){  
          alert("success call"+result);
        },
        error: function(XMLHttpRequest, textStatus, errorThrown) { 
            alert("Status: " + textStatus); alert("Error: " + errorThrown); 
        }                 
      });  
    }        
    </script>
    <title>My AJAX</title>
</head>
<body>
    <button type="button" onclick="login()">Click Me!</button>
</body>


函数login（）{
$.ajax（{
类型：“POST”，
url:“http://localhost:8080/test/toto",  
数据：“通话后”，
成功：函数（结果）{
警报（“成功呼叫”+结果）；
},
错误：函数（XMLHttpRequest、textStatus、ErrorSprown）{
警报（“状态：+textStatus”）；警报（“错误：+ERRORSHORN”）；
}                 
});  
}        
我的阿贾克斯
点击我！
我用浏览器测试了servlet，没问题。当我尝试HTML/js应用程序并点击eclipse控制台中的按钮时，指示系统.out.println（getBody（request））显示的消息；“POST Call”但我在浏览器中收到了错误警报。因此，ajax函数成功地调用了servlet中的方法post，但servlet无法成功地将响应返回给浏览器。似乎servlet中存在问题。有人能帮我吗？

在
doPost（）中尝试添加请求标题：


response.setContentType("text/html"); 
response.setHeader("Access-Control-Allow-Origin", "*"); 



我确信这与所描述的允许原点问题有关，它是特定于浏览器的

它在Safari 8.0.3上运行良好，在Chrome和Firefox上抛出错误
没有“Access Control Allow Origin”标题

查看Firefox中的控制台：

已阻止跨源请求：同一源策略不允许读取位于的远程资源。这可以通过将资源移动到同一域或启用CORS来解决

可以通过在浏览器中禁用
web安全性
或如前所述进行修复：


response.setHeader（“访问控制允许来源”，您的_域）
如果显示“POST Call”，则ajax中的数据“POST Call”中可能存在问题。。如果您使用的是chrome浏览器，也可以查看网络选项卡上的响应和标题。我尝试了firefox和chrome，但收到了相同的错误警报。但在chrome中，当我点击按钮时，我也收到了这个错误消息：XMLHttpRequest无法加载。请求的资源上不存在“Access Control Allow Origin”标头。因此不允许访问源“null”。是否使用iframe加载servlet？\n否我不在
doPost（）中使用iframe加载，请尝试添加请求头：
response.setContentType（“text/html”）；response.setHeader（“访问控制允许原点“，“*”）这有什么区别吗？