Question

如何使用ajax调用java类

Answer 1

ajax调用java后台的方法，其实是通过url链接来访问，示例如下：package com.xxxx.xxxx.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

public class oaLoginLimitedServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static Connection conn=null;
private static PreparedStatement pstmt=null;

public oaLoginLimitedServlet() {
super();
}

public void destroy() {
super.destroy();
}

public static String getCount(String userid)
{
String v_sql=".....";
String v_count="";

try {
pstmt = conn.prepareStatement(v_sql);
pstmt.setString(1, userid);
ResultSet rs = pstmt.executeQuery();
while(rs.next()){
v_count = rs.getString(1);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
pstmt.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return v_count;
}

public static Connection getConnection(){
Context ctx = null;
try {
ctx = new InitialContext();
DataSource ds = (DataSource)ctx.lookup("jndiname");
conn = ds.getConnection();
} catch (Exception e) {
e.printStackTrace();
}
return conn;
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String v_userid=request.getParameter("userid");
System.out.println(v_userid);
getConnection();
String v_count=getCount(v_userid);
response.setCharacterEncoding("UTF-8");
response.getWriter().write(v_count);
response.flushBuffer();
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}

}

如果要前端能够访问到该servlet，需要将该servlet注册到 web.xml文件中。需要在web.xml文件中添加以下内容
[html] view plaincopy
<servlet>
<servlet-name>oaLoginLimitedServlet</servlet-name>
<servlet-class>com.xxxx.xxxx.servlet.oaLoginLimitedServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>oaLoginLimitedServlet</servlet-name>
<url-pattern>/oaLoginLimitedServlet</url-pattern>
</servlet-mapping>

重启相关服务。
通过ajax就可以调用了。

[html] view plaincopy
var msg = $.ajax({
type: "post",
url: ....+'/oaLoginLimitedServlet?userid='+ $('#act').val(),
async:false
}).responseText;
https://zhidao.baidu.com/question/2201763852265627548.html