找不到符号，java，classloader [英] cannot find symbol, java, classloader
问题描述
目前正在进行一个类型状态项目，我在导入List类时遇到问题。当我尝试编译类时，它会在命令行中抛出一个错误，指出找不到符号并指向List符号。我想知道你是如何解决这个问题的。它似乎适用于String和Integer，但不适用于List。
Currently doing a typestate project and I am having problems with importing the List class. When I try to compile the class it throws an error in command line saying cannot find symbol and points to the List symbol. I was wondering how you fix this. It seems to work for String and Integer but not for List.
java文件是通过另一个翻译.scr文件的程序自动创建的。在scr文件中，我使用以下行：
The java file is automatically create via another program that translates .scr files. In the scr file I use the following line :
type <java> "java.lang.List" from "rt.jar" as List;
Java文件：
package demos.Redis;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.ServerSocket;
import java.net.UnknownHostException;
public class ClientRole {
private BufferedReader socketServerIn = null;
private PrintWriter socketServerOut = null;
public ClientRole(){
ServerSocket serverServer = null;
try {
serverServer = new ServerSocket(20000);
}
catch(IOException e) {
System.out.println("Unable to listen on ports");
System.exit(+1);
}
Socket socketServer = null;
try {
System.out.println("Accepting...");
socketServer = serverServer.accept();
System.out.println("Server accepted");
}
catch(IOException e) {
System.out.println("Accept failed");
System.exit(+1);
}
try {
socketServerIn = new BufferedReader(new InputStreamReader(socketServer.getInputStream()));
socketServerOut = new PrintWriter(socketServer.getOutputStream(), true);
}
catch(IOException e) {
System.out.println("Read failed");
System.exit(+1);
}
}
public void send_WATCHListToServer(List payload) { HERE IS WHERE IT BREAKS!!
this.socketServerOut.println(payload);
}
public Choice1 send_Choice1LabelToServer(String payload) {
this.socketServerOut.println(payload);
int intLabelChoice1 = Integer.parseInt(payload);
switch(intLabelChoice1){
case 1:
return new Choice1(Choice1.GET);
case 2:
return new Choice1(Choice1.WATCH);
case 3:
default:
return new Choice1(Choice1.MULTI);
}
}
public void send_GETStringToServer(String payload) {
this.socketServerOut.println(payload);
}
public String receive_GET_respStringFromServer() {
String line = "";
try {
line = this.socketServerIn.readLine();
}
catch(IOException e) {
System.out.println("Input/Outpur error.");
System.exit(+1);
}
return line;
}
public void send_MULTIStringToServer(String payload) {
this.socketServerOut.println(payload);
}
public Choice2 send_Choice2LabelToServer(String payload) {
this.socketServerOut.println(payload);
int intLabelChoice2 = Integer.parseInt(payload);
switch(intLabelChoice2){
case 1:
return new Choice2(Choice2.SET);
case 2:
return new Choice2(Choice2.DISCARD);
case 3:
default:
return new Choice2(Choice2.EXEC);
}
}
public void send_SETStringToServer(String payload) {
this.socketServerOut.println(payload);
}
public void send_DISCARDStringToServer(String payload) {
this.socketServerOut.println(payload);
}
public void send_EXECStringToServer(String payload) {
this.socketServerOut.println(payload);
}
public Choice3 receive_Choice3LabelFromServer() {
String stringLabelChoice3 = "";
try {
stringLabelChoice3 = this.socketServerIn.readLine();
}
catch(IOException e) {
System.out.println("Input/Outpur error, unable to get label");
System.exit(+1);
}
int intLabelChoice3 = Integer.parseInt(stringLabelChoice3);
switch(intLabelChoice3){
case 1:
return new Choice3(Choice3.EXEC_OK);
case 2:
default:
return new Choice3(Choice3.EXEC_FAIL);
}
}
public String receive_EXEC_okStringFromServer() {
String line = "";
try {
line = this.socketServerIn.readLine();
}
catch(IOException e) {
System.out.println("Input/Outpur error.");
System.exit(+1);
}
return line;
}
public String receive_EXEC_failStringFromServer() {
String line = "";
try {
line = this.socketServerIn.readLine();
}
catch(IOException e) {
System.out.println("Input/Outpur error.");
System.exit(+1);
}
return line;
}
}
命令行
推荐答案
您的Java文件缺少java.util.List的import语句，这就是它无法编译的原因。
Your Java file is missing an import statement for java.util.List, which is why it's failing to compile.
与String和Integer不同，List不在java.lang包中。你需要导入java.util.List，而不是java.lang.List。
Unlike String and Integer, List is not in the java.lang package. You need to import java.util.List, not java.lang.List.
如果我正确理解你的场景，你的其他程序正在生成import语句和尝试为java.lang.List添加一个实际上不存在的导入。有趣的是，java.lang.List的代码中没有import语句。我不知道这是你的其他程序或功能中的错误！但是，如果用。code>类型< java>替换.scr文件中的行，你的问题很可能会消失。 rt.jar中的java.util.List为List;
If I'm understanding your scenario correctly, your other program is generating the import statements and attempting to add an import for java.lang.List, which doesn't actually exist. Interestingly, there's no import statement in your code for java.lang.List. I don't know if that's a bug in your other program or a feature! But more than likely your problem will go away if you replace your line in the .scr file with type <java> "java.util.List" from "rt.jar" as List;
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