获取完整的方法体字符串
时间: 2023-10-25 10:07:48 浏览: 30
要获取完整的Java方法体字符串,可以使用Java编译器API或第三方库来实现。以下是使用Java编译器API的示例代码:
```java
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class MethodBodyToString {
public static String getMethodBodyAsString(Class<?> clazz, String methodName, Class<?>... parameterTypes) throws IOException {
// 获取方法的源代码
String methodSource = getMethodSource(clazz, methodName, parameterTypes);
// 将源代码写入临时文件
Path tempFile = Files.createTempFile("MethodBodyToString", ".java");
Files.write(tempFile, methodSource.getBytes(StandardCharsets.UTF_8));
// 编译临时文件并获取类文件
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
Iterable<? extends JavaFileObject> compilationUnits = fileManager.getJavaFileObjects(tempFile.toFile());
StringWriter writer = new StringWriter();
JavaCompiler.CompilationTask task = compiler.getTask(writer, fileManager, null, null, null, compilationUnits);
boolean success = task.call();
if (!success) {
throw new RuntimeException("Compilation failed");
}
byte[] classBytes = Files.readAllBytes(Paths.get(clazz.getResource(clazz.getSimpleName() + ".class").getPath()));
// 使用ASM库解析类文件并获取方法体
ClassNode classNode = new ClassNode();
ClassReader classReader = new ClassReader(classBytes);
classReader.accept(classNode, 0);
MethodNode methodNode = null;
for (MethodNode node : classNode.methods) {
if (node.name.equals(methodName) && Arrays.equals(getParameterTypes(node), parameterTypes)) {
methodNode = node;
break;
}
}
if (methodNode == null) {
throw new NoSuchMethodException("Method not found: " + clazz.getName() + "." + methodName);
}
// 使用Textifier类将方法体转换为字符串
StringWriter methodWriter = new StringWriter();
TraceMethodVisitor methodVisitor = new TraceMethodVisitor(null, new Textifier(), methodWriter);
methodNode.accept(methodVisitor);
return methodWriter.toString();
}
private static String getMethodSource(Class<?> clazz, String methodName, Class<?>... parameterTypes) throws NoSuchMethodException, IOException {
Method method = clazz.getMethod(methodName, parameterTypes);
String className = clazz.getSimpleName();
String methodNameWithParams = method.getName() + "(" + getParameterTypeNames(method.getParameterTypes()) + ")";
String methodBody = method.toString().substring(method.toString().indexOf("{"));
return "public class " + className + " {\n" +
" public static " + method.getReturnType().getSimpleName() + " " + methodNameWithParams + methodBody + "\n" +
"}";
}
private static String getParameterTypeNames(Class<?>[] parameterTypes) {
return Arrays.stream(parameterTypes).map(Class::getSimpleName).collect(Collectors.joining(", "));
}
private static Class<?>[] getParameterTypes(MethodNode methodNode) {
Type[] argumentTypes = Type.getArgumentTypes(methodNode.desc);
Class<?>[] parameterTypes = new Class<?>[argumentTypes.length];
for (int i = 0; i < argumentTypes.length; i++) {
parameterTypes[i] = toClass(argumentTypes[i]);
}
return parameterTypes;
}
private static Class<?> toClass(Type type) {
switch (type.getSort()) {
case Type.BOOLEAN:
return boolean.class;
case Type.BYTE:
return byte.class;
case Type.CHAR:
return char.class;
case Type.SHORT:
return short.class;
case Type.INT:
return int.class;
case Type.LONG:
return long.class;
case Type.FLOAT:
return float.class;
case Type.DOUBLE:
return double.class;
case Type.ARRAY:
return Array.newInstance(toClass(type.getElementType()), 0).getClass();
case Type.OBJECT:
try {
return Class.forName(type.getClassName());
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
default:
throw new IllegalArgumentException("Unsupported type: " + type);
}
}
}
```
该方法先获取Java方法的源代码,然后将源代码写入临时文件,编译临时文件并获取类文件,最后使用ASM库解析类文件并获取方法体。注意需要将ASM库添加到项目中。你可以在方法体中修改具体的类名、方法名和参数类型来获取不同的方法体。