Persistent preservation of object flow using very hard-core JAVA serialization

• background
• The concept of object flow
• Object Flow Instances
  • Introduce an Organization Chart
  • Define Classes for Organization Schema Diagram
    • The complete structure of the class
  • Save object information for organization architecture with object flow
    • Core Code
  • Read files and output with object stream
    • Core Code
• summary

To achieve persistent object preservation, we need to introduce the Java object serialization mechanism, which can output any object to the stream:

/** *Stream Object */ Object object = new Object(); //Create object stream and output to fileObject.dat ObjectOutputStream output = new ObjectOutputStream(new FileOutputStream("c:\\object.dat")); //Write object to file output.writeObject(object); ObjectInputStream input = new ObjectInputStream(new FileInputStream("c:\\object.dat")); object = input.readObject();

• Company: Represents the external presence of the organizational structure; the company is a complete entity composed of departments and staff.
• Departments: Represents the units of operation in the organizational structure; Departments can be divided into different business units by type.
• Employee: Represents the smallest unit in the organization structure; employees exist in different business units by position.

/** * Save Information with Object Flow--Company Class * * @author zhuhuix * @date 2020-05-27 */ class Company implements Serializable { //Company id private int id; //Corporate name private String name; //List of company departments private List<Department> departments; //Default constructor Company() { } //Initialization Constructor Company(int id, String name) { this.id = id; this.name = name; this.departments = new ArrayList<>(); } //Additional departments public void addDepartment(Department department) { this.departments.add(department); } //Cancellation of Departments public void deleteDepartment(Department department) { this.departments.remove(department); } //Location Department Department findDepartmentByName(String departmentName) { Optional<Department> optional = departments.stream().filter(department -> department.getName().equals(departmentName)).findFirst(); return optional.get(); } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public List<Department> getDepartments() { return departments; } public void setDepartments(List<Department> departments) { this.departments = departments; } } /** * Save Information with Object Flow--Department Class * * @author zhuhuix * @date 2020-05-27 */ class Department implements Serializable { //Department id private int id; //Department Name private String name; //Superior departments private Integer parentId; //Department Staff List private List<Employee> employees; //Default constructor Department(){} //Initialization Constructor Department(int id,String name,Integer parentId){ this.id=id; this.name=name; this.parentId=parentId; this.employees = new ArrayList<>(); } //Add staff public void addEmployee(Employee employee){ this.employees.add(employee); } //Remove staff public void deleteEmployee(Employee employee){ this.employees.remove(employee); } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getParentId() { return parentId; } public void setParentId(Integer parentId) { this.parentId = parentId; } public List<Employee> getEmployees() { return employees; } public void setEmployees(List<Employee> employees) { this.employees = employees; } } /** * Save Information with Object Flow--Staff Class * * @author zhuhuix * @date 2020-05-27 */ class Employee implements Serializable { //Employee id private int id; //Employee Name private String name; //Employee gender private String sex; //Employee age private int age; //Employee position private String position; //Date of entry private Date hireDate; //Current salary private BigDecimal salary; //Default constructor Employee(){} //Initialization Constructor public Employee(int id, String name, String sex, int age, String position, Date hireDate, BigDecimal salary) { this.id = id; this.name = name; this.sex = sex; this.age = age; this.position = position; this.hireDate = hireDate; this.salary = salary; } //Promotion, transfer, transfer public void setPosition(String position){ this.position = position; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getPosition() { return position; } public Date getHireDate() { return hireDate; } public void setHireDate(Date hireDate) { this.hireDate = hireDate; } public BigDecimal getSalary() { return salary; } public void setSalary(BigDecimal salary) { this.salary = salary; } }

With classes and constructors that complete the initialization of objects, we have the ability to build an entire organizational structure. Next, we build a complete organizational structure for the company:

/** 1. Save organization architecture information with object flow 2. * @author zhuhuix 3. @date 2020-05-27 */ public class ObjectStreamSave { //Define a global static variable as the id that controls the organization's architecture public static int id = 0; public static void main(String[] args) throws IOException { //establishment of company Company company = new Company(id++, "Internet Co., Ltd."); //The company establishes the general manager's Office Department manageDept = new Department(id++, "General Manager Office", null); company.addDepartment(manageDept); //Set up Product Department under General Manager Department productDept = new Department(id++, "Product Department", manageDept.getId()); company.addDepartment(productDept); //Set up Group A and Group B under Product Department company.addDepartment(new Department(id++, "product A group", productDept.getId())); company.addDepartment(new Department(id++, "product B group", productDept.getId())); //Set up R&D department under General Manager's Office Department developmentDept = new Department(id++, "R&D Department", manageDept.getId()); company.addDepartment(developmentDept); //Set up software and hardware groups under R&D Department company.addDepartment(new Department(id++, "Software Group", developmentDept.getId())); company.addDepartment(new Department(id++, "Hardware Group", developmentDept.getId())); //Set up Marketing Department under General Manager Department marketDept = new Department(id++, "Marketing Department", manageDept.getId()); company.addDepartment(marketDept); //Set up Creative Group and Channel Group under Marketing Department company.addDepartment(new Department(id++, "Creative Group", marketDept.getId())); company.addDepartment(new Department(id++, "Channel Group", marketDept.getId())); //Personnel appointment in general manager's Office manageDept.addEmployee(new Employee(id++, "Mike", "male", 35, "General manager", new Date(), BigDecimal.valueOf(100000))); manageDept.addEmployee(new Employee(id++, "Tom", "male", 34, "Vice General Manager", new Date(), BigDecimal.valueOf(60000))); //R&D Personnel Appointment developmentDept.addEmployee(new Employee(id++, "Jack", "male", 30, "Director of R&D", new Date(), BigDecimal.valueOf(40000))); company.findDepartmentByName("Software Group") .addEmployee(new Employee(id++, "Kate", "female", 26, "Group members", new Date(), BigDecimal.valueOf(20000))); company.findDepartmentByName("Hardware Group") .addEmployee(new Employee(id++, "Will", "male", 24, "Group members", new Date(), BigDecimal.valueOf(20000))); //Personnel Appointment for Product Department productDept.addEmployee(new Employee(id++, "Jerry", "male", 28, "Product Director", new Date(), BigDecimal.valueOf(40000))); company.findDepartmentByName("product A group") .addEmployee(new Employee(id++, "Merry", "female", 28, "Group members", new Date(), BigDecimal.valueOf(20000))); company.findDepartmentByName("product B group") .addEmployee(new Employee(id++, "Leo", "male", 27, "Group members", new Date(), BigDecimal.valueOf(20000))); //Marketing Personnel Appointment marketDept.addEmployee(new Employee(id++, "Rose", "female", 29, "Marketing Director", new Date(), BigDecimal.valueOf(40000))); company.findDepartmentByName("Creative Group") .addEmployee(new Employee(id++, "Amy", "", 25, "Group members", new Date(), BigDecimal.valueOf(20000))); company.findDepartmentByName("Channel Group") .addEmployee(new Employee(id++, "Tony", "male", 23, "Group members", new Date(), BigDecimal.valueOf(20000))); //Traverse company organization structure int deptCount = 0; int empCount = 0; Iterator<Department> deptIterator = company.getDepartments().iterator(); while (deptIterator.hasNext()) { deptCount++; Department department = deptIterator.next(); System.out.println("department:" + department.getName()); if (department.getEmployees() != null) { Iterator<Employee> empIterator = department.getEmployees().iterator(); while (empIterator.hasNext()) { empCount++; Employee employee = empIterator.next(); System.out.print(" personnel:" + employee.getName() + " position:" + employee.getPosition() + ","); } System.out.println(); } } System.out.println("Total number of departments:" + deptCount); System.out.println("Total number of employees:" + empCount); //Save company organization structure to file through object flow ObjectOutputStream companyStream = new ObjectOutputStream(new FileOutputStream("c:\\company.dat")); companyStream.writeObject(company); companyStream.writeObject(company.getDepartments()); for (int i = 0; i < company.getDepartments().size(); i++) { List<Employee> employees = company.getDepartments().get(i).getEmployees(); companyStream.writeObject(employees); } } }

1. Create a stream of objectsCompany.datfile
2. Write Company objects to files
3. Write the Department list collection in the company object to a file
4. Traverse Department lists and write a collection of employee lists under each department to a file

The resulting files are as follows:

Binary information:

/** * Reading information with object streams * * @author zhuhuix * @date 2020-05-27 */ public class ObjectStreamRead { public static void main(String[] args) throws IOException, ClassNotFoundException { ObjectInputStream companyStream = new ObjectInputStream(new FileInputStream("c:\\company.dat")); if (companyStream!=null){ Company company=(Company) companyStream.readObject(); //Traverse company organization structure int deptCount = 0; int empCount = 0; Iterator<Department> deptIterator = company.getDepartments().iterator(); while (deptIterator.hasNext()) { deptCount++; Department department = deptIterator.next(); System.out.println("department:" + department.getName()); if (department.getEmployees() != null) { Iterator<Employee> empIterator = department.getEmployees().iterator(); while (empIterator.hasNext()) { empCount++; Employee employee = empIterator.next(); System.out.print(" personnel:" + employee.getName() + " position:" + employee.getPosition() + ","); } System.out.println(); } } System.out.println("Total number of departments:" + deptCount); System.out.println("Total number of employees:" + empCount); } } }

1. Obtain by Object StreamCompany.datfile
2. Read object information

The output is as follows:

In this article, we use serialization to save collections of objects to disk files and get them as they are stored. We learned the following:

• ObjectOutputStream (OutputStream out) creates an ObjectOutputStream that allows you to write out objects to the specified OutputStream.
• Void writeObject (Object obj) writes the specified object to ObjectOutputStream, which stores the class of the specified object, the signature of the class, and the values of all non-static and non-instantaneous fields in the class and its superclass.
• ObjectInputStream (InputStream in) creates an ObjectInputStream to read object information from the specified InputStream.
• Object readObject() reads an object from ObjectInputStream.In particular, this method reads back the class of the object, the signature of the class, and the values of all non-static and non-instantaneous fields in the class and its superclass.The deserialization it performs allows multiple object references to be recovered.

27 May 2020, 21:44 | Views: 3546