Application of SOAP protocol based on J2ME platform

J2ME, as an embedded system application platform, has developed rapidly, and the inherent platform independence of Java language makes the embedded application system based on J2ME platform have broad foreground. Restricted by the limitations of embedded devices and consumer electrical hardware, the J2ME platform provides limited functions, how to expand the function of J2ME under limited resources, so that the J2ME platform can handle the SOAP protocol is the focus of this paper.

At present, enterprise application is transforming to the SOA architecture oriented to Web service, and the connection between embedded system and enterprise application system is still in the primary stage of TCP/IP protocol and HTTP protocol. With the increasing breadth and maturity of Web services provided by enterprise application Systems, there is a growing demand for J2ME platforms to handle SOAP protocols.

SOA architecture is currently a widely deployed architecture for enterprise applications, and one of the key issues in implementing SOA is support for the SOAP protocol. This paper analyzes the problems encountered in implementing SOAP protocol processing in J2ME platform, and puts forward the corresponding solutions.

First, J2ME introduction

J2ME (Java 2 Platform Micro Edition) is a Java platform designed for the wireless electronics market, including JVM specifications and API specifications. J2ME defines a set of class libraries and virtual machine technologies that enable users, service providers, and device manufacturers to use rich applications whenever they need them, either through physical (wired) or wireless connections. J2ME also provides the consistent cross-platform and security of the Java language.

To support the flexibility and customization requirements presented by users and embedded markets, J2ME is designed to be more modular and scalable. J2ME built 3-tier software on the original operating system of the device to achieve this requirement:

1. JVM Layer: This layer is based on the host operating system, and the JVM is implemented in a J2ME configuration.

2. Configuration layer: This layer is less visible to the user, but very important to the surface. It defines the minimum set of functions for Java virtual machines and the smallest collection of Java class libraries for different market needs. In J2ME devices, the JVM is closely connected to the configuration layer, which embodies the basic functionality of each type of device.

3. Simple surface: This layer is most common to users and application providers. It defines the minimum set of functions for a Java Virtual machine and the smallest collection of Java class libraries for specific market needs.

The J2ME components revolve around a center, which is called the configuration (configuration), and each of them is a special class for consumer electronics and embedded devices. The current configuration is divided into CLDC and CDC two kinds.

Connected Limited Device configuration (limited-connection device configuration, short CLDC) defines the application interfaces and technologies that support "devices", hold in your hand (holding devices in hand), and such devices The representative is a PDA. Connected device configuration (connect device configuration CDC) defines the application interfaces and technologies that support "devices" to plug into the plug (device for inserting walls), which are represented by Stb.

The differences between the two configurations lie in the ability of the devices they apply to, the limited processor capacity of the CLDC device (compared to the desktop system), and the memory size generally only between 128 KB and KB. Unlike the CDC system, it may have 32-bit or 64-bit processors, as well as limited storage capacity, but it has a lower limit of more than 512K.

The relevant pictures of this topic are as follows:

The diagram above explains the architecture of configuration and summary tables. The architecture of J2ME is divided into three layers horizontally and divided into two parts vertically. The configuration includes a virtual machine that controls the core classes of the configuration, and the specific table is located above each configuration.

The summary table provides a standardized Java class library for different manufacturers of the same consumer electronics devices, and now has five known summary tables that have been standardized:

Mobile Information Devices profile (MIDP) cellular phone and pager CLDC

Personal Digital Assistant Profile Palm and Handspring PDA equipment CLDC

Standard summary of Foundation profile for all CDC devices that do not require a GUI CDC

Personal Profile replaces Personaljava's foundation perfect summary of the CDC

RMI Profile provides RMI Foundation perfect summary of the CDC