Java提示构造函数中泄漏 this，怎么解决？

Question

我是添加按钮Button监控时出错的Button.addActionListener(this)

Answer 1

Button b = new Button();
 b.addActionListener(this);
this类必须实现 Event事件,才能让this监听

Answer 2

Button b = new Button();
 b.addActionListener(this);
其实我忘记说了，我已经加了Button的对象button1了，不过还是出现那个提示提示构造函数中泄漏 this
import java.awt.*;
import java.awt.Font.*;
import java.awt.event.*;
import java.util.Date;
import javax.swing.*;
import java.sql.*;
import  com.dbmanage.*;
public class Dl_Zc extends JFrame  implements Runnable , ActionListener {
          public String YH_Name;
        public  String Sex1;
         public String  JG;
          public  String DZ;
           public  String phone;
               public  String MM;
           public  String E_Mail;
    Thread thread2=new Thread(this);
    Label lable10=new Label("用户注册界面");
      Label lable1=new Label("用户昵称");
        Label lable11=new Label("性别");
Choice sex=new Choice();
        Label lable2=new Label("籍贯");
        Label lable3=new Label("地址");
        Label lable4=new Label("联系方式");
        Label lable5=new Label("新密码");
        Label lable6=new Label("确认密码");
        Label lable7=new Label("E_Mail");
        JButton Button1=new JButton("注册");
              JButton Button2=new JButton("取消");
              TextField text1=new     TextField (5);
               TextField text2=new     TextField (10);
               TextField text3=new     TextField (20);
               TextField text4=new     TextField (15);
             TextField text5=new     TextField (10);
                TextField text6=new     TextField (10);
                TextField text7=new     TextField (15);
       Dl_Zc(){
      
        Box baseBox ,baseBox0 ,boxV0,boxV1,boxV2,boxV3,boxV5,boxV4;
    boxV0=Box.createVerticalBox();
      boxV0.add(lable10);
        lable10.setFont(new java.awt.Font("SansSerif",1,20));
               lable10.setForeground(Color.red);
       boxV1=Box.createVerticalBox();
      boxV1.add(lable1);
       boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable11);
      boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable2);
      boxV1.add(Box.createVerticalStrut(38));
       boxV1.add(lable3);
      boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable4);
        boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable5);
       boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable6);
        boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable7);
      //boxV1.add(Box.createVerticalStrut(138));
     // boxV1.add(button1);
      boxV2=Box.createVerticalBox();      boxV2.add(text1);
             boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(sex);
           boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text2);
      boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text3);
      boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text4);
       boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text5);
             boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text6);
             boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text7);         boxV5=Box.createHorizontalBox();
      boxV5.add(Button1);
      boxV5.add(Box.createHorizontalStrut(60));
     boxV5.add(Button2);      baseBox=Box.createHorizontalBox();
      baseBox.add(boxV1);
      baseBox.add(Box.createHorizontalStrut(2));
      baseBox.add(boxV2);       baseBox0=Box.createVerticalBox();
      baseBox0.add(boxV0);
      baseBox0.add(Box.createVerticalStrut(38));
       baseBox0.add( baseBox);
       baseBox0.add(Box.createVerticalStrut(38));
       baseBox0.add(  boxV5);
      setLayout(new FlowLayout());      add(baseBox0);
      sex.add("男");
            sex.add("女");
             // Button1.addActionListener(this);
                 //      Button2.addActionListener(this);
      
       }
        public void run()
    {}
public void actionPerformed(ActionEvent e){
       // if(e.getSource()==Button1）{
            YH_Name=text1.getText().trim();
            Sex1=sex.getSelectedItem().trim();
            JG=text2.getText().trim();
            DZ=text3.getText().trim();
           phone=text4.getText().trim();
            MM=text5.getText().trim();            E_Mail=text7.getText().trim();
        // String  insertString="INSERT INTO Accout VALUES("+"'"+IDint2+"'"+","+"'"+Khmc1+"'"+","+"'"+spmc1+"'"+","
          //  +jg1+","+"'"+MH1+"'"+","
          //  +"'"+ ks1+"'"+","+"'"+ys1+"'"+","+"'"+ml1+"'"+","+"'"+sl1+"'"+","+zjg1+","+"'"+IsBill1+"'"+","+"'"+nowTime+"'"+")";    try{
    JDBCFile conn2= new JDBCFile();
//    int flag=conn2.insert(insertString);
   
    }
          catch(Exception ee){
           System.out.println(ee);
       }
 JOptionPane.showMessageDialog(null, "    提交成功！","系统信息", JOptionPane.PLAIN_MESSAGE);
        }
}
//}

Answer 3

这个提示错误比较明显：import java.awt.*;
import java.awt.Font.*;
import java.awt.event.*;
import java.util.Date;
import javax.swing.*;
import java.sql.*;
import  com.dbmanage.*;
public class Dl_Zc extends JFrame  implements Runnable , ActionListener {
          public String YH_Name;
        public  String Sex1;
         public String  JG;
          public  String DZ;
           public  String phone;
               public  String MM;
           public  String E_Mail;
    Thread thread2=new Thread(this);
    Label lable10=new Label("用户注册界面");
      Label lable1=new Label("用户昵称");
        Label lable11=new Label("性别");
Choice sex=new Choice();
        Label lable2=new Label("籍贯");
        Label lable3=new Label("地址");
        Label lable4=new Label("联系方式");
        Label lable5=new Label("新密码");
        Label lable6=new Label("确认密码");
        Label lable7=new Label("E_Mail");
        JButton Button1=new JButton("注册");
              JButton Button2=new JButton("取消");
              TextField text1=new     TextField (5);
               TextField text2=new     TextField (10);
               TextField text3=new     TextField (20);
               TextField text4=new     TextField (15);
             TextField text5=new     TextField (10);
                TextField text6=new     TextField (10);
                TextField text7=new     TextField (15);
       Dl_Zc(){
      
        Box baseBox ,baseBox0 ,boxV0,boxV1,boxV2,boxV3,boxV5,boxV4;
    boxV0=Box.createVerticalBox();
      boxV0.add(lable10);
        lable10.setFont(new java.awt.Font("SansSerif",1,20));
               lable10.setForeground(Color.red);
       boxV1=Box.createVerticalBox();
      boxV1.add(lable1);
       boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable11);
      boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable2);
      boxV1.add(Box.createVerticalStrut(38));
       boxV1.add(lable3);
      boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable4);
        boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable5);
       boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable6);
        boxV1.add(Box.createVerticalStrut(38));
      boxV1.add(lable7);
      //boxV1.add(Box.createVerticalStrut(138));
     // boxV1.add(button1);
      boxV2=Box.createVerticalBox();      boxV2.add(text1);
             boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(sex);
           boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text2);
      boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text3);
      boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text4);
       boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text5);
             boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text6);
             boxV2.add(Box.createVerticalStrut(38));
      boxV2.add(text7);         boxV5=Box.createHorizontalBox();
      boxV5.add(Button1);
      boxV5.add(Box.createHorizontalStrut(60));
     boxV5.add(Button2);      baseBox=Box.createHorizontalBox();
      baseBox.add(boxV1);
      baseBox.add(Box.createHorizontalStrut(2));
      baseBox.add(boxV2);       baseBox0=Box.createVerticalBox();
      baseBox0.add(boxV0);
      baseBox0.add(Box.createVerticalStrut(38));
       baseBox0.add( baseBox);
       baseBox0.add(Box.createVerticalStrut(38));
       baseBox0.add(  boxV5);
      setLayout(new FlowLayout());      add(baseBox0);
      sex.add("男");
            sex.add("女");
             Button1.addActionListener(this);
          Button2.addActionListener(this);
      
       }
        public void run()
    {}
public void actionPerformed(ActionEvent e){
       if(e.getSource()==Button1）{
            YH_Name=text1.getText().trim();
            Sex1=sex.getSelectedItem().trim();
            JG=text2.getText().trim();
            DZ=text3.getText().trim();
           phone=text4.getText().trim();
            MM=text5.getText().trim();            E_Mail=text7.getText().trim();
        // String  insertString="INSERT INTO Accout VALUES("+"'"+IDint2+"'"+","+"'"+Khmc1+"'"+","+"'"+spmc1+"'"+","
          //  +jg1+","+"'"+MH1+"'"+","
          //  +"'"+ ks1+"'"+","+"'"+ys1+"'"+","+"'"+ml1+"'"+","+"'"+sl1+"'"+","+zjg1+","+"'"+IsBill1+"'"+","+"'"+nowTime+"'"+")";    try{
    JDBCFile conn2= new JDBCFile();
//    int flag=conn2.insert(insertString);
   
    }
          catch(Exception ee){
           System.out.println(ee);
       }
 JOptionPane.showMessageDialog(null, "    提交成功！","系统信息", JOptionPane.PLAIN_MESSAGE);
        }
}
}

Answer 4

if(e.getSource()==Button1){
if(e.getSource()==Button1){上面代码 这个括号是中文的改过来,你看你代码  我发的已经改过来了
其他的 我电脑没有找到 JDBCFile  类，其他代码没有问题

Answer 5

谢谢大家！呵呵，我也是发上去才发现是中文括号的错，不过那个this泄露是啥意思，我是初学的，不是很懂。

Answer 6

典型的事件监听机制，Button就是被监听的对象

Answer 7

同问, 每次 addActionListener(this) 都会提示警告, 想从根本上知道为什么, 不怕解释复杂, 只要合理就好.

Answer 8

我今天也遇到了这个问题，感觉是个警告，就是说在构造函数执行的过程中，对象还没有被创建出来，或者说还没有被初始化好，这时把this拿来用，有点不妥当的意思，但仔细想一下，执行构造函数时，对象地址已经分配好，引用this应该是没有问题的，或者说，可能绝大多数情况下没有问题，不知道会不会在某种情况下有问题，提示的警告是“泄漏this”，也许在安全上会有问题吧，期待有更深入的解答，如果有可能的话，先把对象创建好，再用对象的引用去set或调用某方法，这样就不用在构造方法里引用this了，只是考虑一下并发的问题，不要多线程同时调用。另外如果把这个引用this的语句单拿到一个方法里去，在构造方法里去调用这个方法，不会有警告了，只是这是欺骗编译器的一种行为吧，没有从根本上解决在执行构造方法时引用this的问题。