Infinite recursion and Jackson JSON and Hibernate JPA problems

When trying to convert a JPA object with two-way associations to JSON, I kept org.codehaus.jackson.map.JsonMappingException: Infinite recursion (StackOverflowError) All I found was The thread , basically ending with a recommendation to avoid two-way Association. Who knows the wrong solution this spring? ------Edited on July 24, 2010 16 ...

Posted by Xzone5 on Fri, 14 Feb 2020 06:14:15 -0800

MasterSlave cluster deployment of ActiveMQ high availability solution (HA)

In the previous documents, we demonstrated how to use shared files and shared databases to realize the cluster of activemq. See also MasterSlave cluster deployment of ActiveMQ high availability solution (HA) (I) In this section, we demonstrate how to implement clustering through leveldb + zookeeper. O ...

Posted by gjdunga on Fri, 14 Feb 2020 05:31:00 -0800

Java realizes online examination system (administrator function)

In this examination system, the three roles of administrator, teacher and student are equivalent to three systems.Online examination system administrator login pageSubject management page (subject can be added, deleted, modified and checked) /** * Query accounts in pages and show them to the page * ...

Posted by Sfoot on Fri, 14 Feb 2020 05:10:24 -0800

Arrays in Java

In Java, array is a kind of reference data type. It is the simplest compound data type and a collection of ordered data. Each element in the array has the same data type. You can use a uniform array name and different subscripts to determine the unique elements in the array. According to the dimension o ...

Posted by Ruiser on Fri, 14 Feb 2020 03:23:36 -0800

Data structure (tree)

1, Binary sort tree Definition: the value of the left subtree is less than the value of the parent node, and the value of the right subtree is greater than the value of the parent node. All nodes meet this definition. Delete: in three cases ① If the deleted node is a leaf node, you can delete it direc ...

Posted by CBaZ on Fri, 14 Feb 2020 00:36:57 -0800

Two encoding formats for Post requests: application/x-www-form-urlencoded and multipart/form-data

In common business development, POST requests are often used in these places: when front-end forms are submitted, when interface code is invoked, and when the Postman test interface is used.Let's take a look: 1. When a front-end form is submitted application/x-www-form-urlencoded Form code: <form action="http:// ...

Posted by buzzed_man on Thu, 13 Feb 2020 20:00:26 -0800

Escaping and canceling the escape of html special characters in java

1, Requirement description 1. The data from the front end is stored in the database, which needs to be escaped after the background When the user fills in the data, sometimes some html special characters (such as trademark symbol) will be passed in. At this time, we need to escape the special characters from the front end, an ...

Posted by cueball2000uk on Thu, 13 Feb 2020 14:01:19 -0800

[Java_22] JDK New

JDK 1.8 New 1. Functional interface 1. Functional interface (1) Concepts *Interfaces with only one abstract method (2) Format @FunctionalInterface //Use this comment to determine if the interface is a functional interface. public class class name { public abstract return value method name (parameter list); } 2. Funct ...

Posted by starnol on Thu, 13 Feb 2020 12:55:40 -0800

The problem of uploading files from Android app to spingMVC server

First, upload the code. The encapsulation tool class of the uploaded file is as follows: import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; im ...

Posted by jfdutcher on Thu, 13 Feb 2020 12:20:50 -0800

Python merging multiple Excel data

Installation module 1. Find the corresponding module http://www.python-excel.org/ 2. Install with pip install pip install xlrdpip install XlsxWriter pip list view XlsxWriter example 1 import xlsxwriter 2 3 # Create a workbook and add a worksheet 4 workbook = xlsxwriter.Workbook("demo.xlsx") 5 worksheet = workbook.add ...

Posted by strudo on Thu, 13 Feb 2020 10:23:09 -0800