digester parser error java.lang.NoSuchMethodException: Employee.<init>()

问题

I am trying to parse an xml using digester .

My XML

<root>
<Employee>
    <Id>1</Id>
    <FirstName>Charles</FirstName>
    <LastName>Madigen</LastName>
    <Location>Louisiana</Location>
    <Skill>Accountant</Skill>
</Employee>
</root>

My Employee class

public class Employee { 
    private int empId;
    private String fName;
    private String lName;
    private String location;
    private String skill;   
    public Employee(int empId, String fName, String lName, String location,
            String skill) {
        this.empId = empId;
        this.fName = fName;
        this.lName = lName;
        this.location = location;
        this.skill = skill;
    }
    @Override
    public String toString() {
        return "Employee [empId=" + empId + ", fName=" + fName + ", lName="
                + lName + ", location=" + location + ", skill=" + skill + "]";
    }

    public void setEmpId(int empId) {
        this.empId = empId;
    }

    public void setfName(String fName) {
        this.fName = fName;
    }

    public void setlName(String lName) {
        this.lName = lName;
    }

    public void setLocation(String location) {
        this.location = location;
    }
    public void setSkill(String skill) {
        this.skill = skill;
    }

}

and my reader class

public class CSVtoXMLTransformer {

    public static void main(String[] args) throws IOException  {        
        CSVtoXMLTransformer cx=new CSVtoXMLTransformer();
        //cx.transfromer();
        cx.validator();
    }                               

    void validator() throws IOException{                        
        String itemTag = "root/Employee";
        Digester digester = new Digester();
        digester.setValidating(false);
        digester.addObjectCreate(itemTag, "assignment3.Employee");
        digester.addCallMethod(itemTag + "/Id", "setEmpId", 0);
        digester.addCallMethod(itemTag + "/FirstName", "setfName", 0);
        digester.addCallMethod(itemTag + "/LastName", "setlName", 0);
        digester.addCallMethod(itemTag + "/Location", "setLocation", 0);
        digester.addCallMethod(itemTag + "/Skill", "setSkill", 0);   

          File inputFile = new File( "generatedEmployee.xml" );
          Employee emp;
        try {
            emp = (Employee)digester.parse( inputFile );
             System.out.println(emp);
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }                               
    }        
}

But while running I am getting this error, Can any one help me on this

org.xml.sax.SAXParseException; systemId: file:/D:/workspace/poc2/generatedEmployee.xml; lineNumber: 2; columnNumber: 11; Error at line 2 char 11: assignment3.Employee
    at org.apache.commons.digester.Digester.createSAXException(Digester.java:3363).......
Caused by: java.lang.NoSuchMethodException: assignment3.Employee.<init>()
    at java.lang.Class.getConstructor0(Unknown Source)
    ... 17 more.....

回答1:

Caused by: java.lang.NoSuchMethodException: assignment3.Employee.<init>()
    at java.lang.Class.getConstructor0(Unknown Source)

Method with signature assignment3.Employee.<init>() is not found in your compiled code that's why JVM raised java.lang.NoSuchMethodException Exception.

In your class you have created parametrized constructor, when you create parameterized constructor compiler will not create default constructor so you have to implement default constructor as well.

回答2:

You need a default constructor in your employee class:

public class Employee { 
    private int empId;
    private String fName;
    private String lName;
    private String location;
    private String skill;   

    public Employee(){}; //Default constructor

    public Employee(int empId, String fName, String lName, String location,
            String skill) {
        this.empId = empId;
        this.fName = fName;
        this.lName = lName;
        this.location = location;
        this.skill = skill;
    }
    @Override
    public String toString() {
        return "Employee [empId=" + empId + ", fName=" + fName + ", lName="
                + lName + ", location=" + location + ", skill=" + skill + "]";
    }
...
}

来源：https://stackoverflow.com/questions/34718226/digester-parser-error-java-lang-nosuchmethodexception-employee-init