Question

我想通过gson和一个类获得信息形式的mysql数据库。我总是得到同样的错误

错误

Exception in thread "AWT-EventQueue-0" java.lang.RuntimeException: Failed to invoke public plugin() with no args
at com.google.gson.internal.ConstructorConstructor$2.construct(ConstructorConstructor.java:98)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:163)
at com.google.gson.Gson.fromJson(Gson.java:755)
at com.google.gson.Gson.fromJson(Gson.java:694)
at gui_gimp$5.mouseClicked(gui_gimp.java:361)
at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:270)
at java.awt.Component.processMouseEvent(Component.java:6538)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6300)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4534)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

引起：java.lang.Error：未解决的编译问题：令牌上的语法错误＆＃34; void＆＃34;，volatile expected

at plugin.<init>(plugin.java:66)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.google.gson.internal.ConstructorConstructor$2.construct(ConstructorConstructor.java:91)
... 36 more

我的班级

public class plugin{

public int id = 0;
public String title = null;
public String link= null;
public String text = null;
public String cat= null;
public String end= null;
public String date= null;
public int rating = 0;

public int getId(){
    return id;
}

public String gettitle(){
    return title;
}
public void settitle(String title){
    this.title = title;
}
public String getlink(){
    return link;
}
public void setlink(String link){
    this.link = link;
}

public String gettext(){
    return text;
}
public void settext(String text){
    this.text = text;
}
public String getcat(){
    return cat;
}
public void setcat(String cat){
    this.cat = cat;
}
public String getend(){
    return end;
}
public void setend(String end){
    this.end = end;
}
public String getdate(){
    return date;
}
public void setdate(String date){
    this.date = date;
}

public int getRating(){
    return rating;
}

}

我的代码

String result ="";
                        try {
                            URL url = new URL("http://calc-o-meter.de/connect/getjson.php");
                            InputStream is = url.openStream();
                            BufferedReader br = new BufferedReader(new InputStreamReader(is));

                            String line;
                            while ( (line = br.readLine()) != null)
                            result = result + line;
                            br.close();
                            is.close();

                        } catch (Exception e1) {
                            e1.printStackTrace();
                        }                                

                        try{


                       Gson gson = new Gson();   
                        plugins = gson.fromJson(result, plugin[].class);
                        System.out.println("GSON "+result)
                        ;



                    } catch (IOException e1) {
                        // TODO Auto-generated catch block
                        e1.printStackTrace();
                    }

Answer 1

首先使用Capitals作为班级名称

public class Plugin

然后正确地实现一切

Plugin[] plugins = gson.fromJson(result, Plugin[].class);

它会起作用

GSON Mysql to class无法调用没有args的公共插件（）

1 个答案: