javaassist的用法

向右看齐 2022-12-16 09:10 228阅读 0赞

package com.dasenlin.baidu;
    
    import java.io.IOException;
    
    import javassist.CannotCompileException;
    import javassist.ClassPool;
    import javassist.CtClass;
    import javassist.CtConstructor;
    import javassist.CtField;
    import javassist.CtMethod;
    import javassist.NotFoundException;
    
    /**
     * 测试javaAssist对java字节码文件进行直接操作
     * @author Administrator
     *
     */
    public class TestJavaAssist {
    
        /**
         * @param args
         */
        public static void main(String[] args) {
            //创建class池
            ClassPool pool = ClassPool.getDefault();
            CtClass cc = pool.makeClass("com.dasenlin.bean.Employ");
            //创建属性
            try {
                CtField f1 = CtField.make("private Integer empId;", cc);
                CtField f2 = CtField.make("private String empName;",cc);
                CtField f3 = CtField.make("private Integer empAge;", cc); 
    
                cc.addField(f1);
                cc.addField(f2);
                cc.addField(f3);
    
                CtMethod m1=CtMethod.make("public Integer getEmpId(){return empId;}", cc);
                CtMethod m2=CtMethod.make("public void setEmpId(Integer empId){this.empId=empId;}", cc);
    
                cc.addMethod(m1);
                cc.addMethod(m2);
    
                CtConstructor constructor =new CtConstructor(new CtClass[]{CtClass.intType,pool.get("java.lang.String")},cc);
                constructor.setBody("{this.empId=empId;this.empName=empName;this.empAge=empAge;}");
                cc.addConstructor(constructor);
                cc.writeFile("E:/LearnJavaProjectText/myjava");
                System.out.println("利用东京大学更简单的操作java字节码文件的jar包javaAssist操作类成功");
            } catch (CannotCompileException e) {
                e.printStackTrace();
            } catch (NotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    }

要先把javaassist.jar导进来。但是我执行这段代码后，反编译后的文件：

package com.dasenlin.bean;
    
    public class Employ {
      private Integer empId = this.empId;
      
      private String empName = this.empName;
      
      private Integer empAge = this.empAge;
      
      public Integer getEmpId() {
        return this.empId;
      }
      
      public void setEmpId(Integer paramInteger) {
        this.empId = paramInteger;
      }
      
      public Employ(int paramInt, String paramString) {}
    }

构造函数里边内容是空。。。。。。。