如何在读取java源文件时查找变量的类型
假设我有一个java源文件（如何在读取java源文件时查找变量的类型,java,parsing,Java,Parsing,假设我有一个java源文件（source.java），如下所示 1 package demo; 2 3 public class Source { 4 5 public static void main(String[] args) { 6 7 String sample = "foo bar"; 8 9 System.out.println(sample.length()); 10 11 } 12 } 现在，我想编写一个java代码，逐
source.java1 package demo;
2
3 public class Source {
4
5 public static void main(String[] args) {
6
7 String sample = "foo bar";
8
9 System.out.println(sample.length());
10
11 }
12 }
samplejava.lang.String要读取独立的java源文件，您必须从头开始，逐行读取，按照java语法解析文件中的每个单词，。。。太多的工作要做。或者我推荐 读取原始Java源文件并将其解析为可以检索信息的Java对象 这是您的问题的示例代码：
public String getSampleVariableType() throws Exception {
// Use the raw text of file as input
// `CompilationUnit` contains all information of your Java file.
CompilationUnit compilationUnit = JavaParser.parse("package demo;\n" +
"\n" +
"public class Source {\n" +
" public static void main(String[] args) {\n" +
" String sample = \"foo bar\"; \n" +
" System.out.println(sample.length());\n" +
" }\n" +
"}");
// Find class by name
ClassOrInterfaceDeclaration clazz = compilationUnit.getClassByName("Source")
.orElse(null);
if (clazz == null)
throw new ClassNotFoundException();
// Find method by name
List<MethodDeclaration> methods = clazz.getMethodsByName("main");
if (methods.size() == 0)
throw new MethodNotFoundException();
// Get the content of method's body
MethodDeclaration method = methods.get(0);
BlockStmt block = method.getBody().orElse(null);
if (block == null)
throw new MethodEmptyException();
// Statement `String sample = "foo bar";` is a VariableDeclaration.
// Find all VariableDeclaration in current method, filter as you want
// and get its class type by using `getType()` method
return block.findAll(VariableDeclarator.class).stream()
.filter(v -> v.getName().asString().equals("sample"))
.map(v -> v.getType().asString())
.findFirst().orElse(null);
}
要读取独立的java源文件，您必须从头开始，逐行读取，按照java语法解析文件中的每个单词，。。。太多的工作要做。或者我推荐 读取原始Java源文件并将其解析为可以检索信息的Java对象 这是您的问题的示例代码：
public String getSampleVariableType() throws Exception {
// Use the raw text of file as input
// `CompilationUnit` contains all information of your Java file.
CompilationUnit compilationUnit = JavaParser.parse("package demo;\n" +
"\n" +
"public class Source {\n" +
" public static void main(String[] args) {\n" +
" String sample = \"foo bar\"; \n" +
" System.out.println(sample.length());\n" +
" }\n" +
"}");
// Find class by name
ClassOrInterfaceDeclaration clazz = compilationUnit.getClassByName("Source")
.orElse(null);
if (clazz == null)
throw new ClassNotFoundException();
// Find method by name
List<MethodDeclaration> methods = clazz.getMethodsByName("main");
if (methods.size() == 0)
throw new MethodNotFoundException();
// Get the content of method's body
MethodDeclaration method = methods.get(0);
BlockStmt block = method.getBody().orElse(null);
if (block == null)
throw new MethodEmptyException();
// Statement `String sample = "foo bar";` is a VariableDeclaration.
// Find all VariableDeclaration in current method, filter as you want
// and get its class type by using `getType()` method
return block.findAll(VariableDeclarator.class).stream()
.filter(v -> v.getName().asString().equals("sample"))
.map(v -> v.getType().asString())
.findFirst().orElse(null);
}
package com.mytest.core.share;
import java.io.File;
import java.io.FileInputStream;
import java.util.Arrays;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.io.IOUtils;
public class TestParse {
public static void main(String[] args) throws Exception {
//testHit();
testNotHit();
}
public static void testNotHit() throws Exception {
// input position
int position = 511;
String id = "sample";
parse(position, id);
}
public static void testHit() throws Exception {
// input position
int position = 955;
String id = "sample";
parse(position, id);
}
public static void parse(int position, String id) throws Exception {
int end = position;
FileInputStream fs = new FileInputStream(new File("TestFile.java"));
String source = IOUtils.toString(fs, "UTF-8");
source = source.substring(0, end);
System.out.println("### look from" +source);
// remove all String in source code;
source = removeStringInSource(source);
int start = 0;
int stack = 0;// for nested scope
boolean hit = false;
// find the char '{' from the end of source
for (int i = source.length(); i > 0; i--) {
String current = source.substring(i - 1, i);
if (stack == 0) {
if (current.equals("{")) {
start = i;// lookup from start to end;
System.err.println("from this {, start to search from the location at " + i);
hit = findInScope(source, id, start, end);
end = start; // skip, search next scope;
if (hit) {
break;
} else {
continue;
}
}
}
// skip bracket pair {}
if (current.equals("}")) {
stack++;
end = i;// skip it;
}
if (current.equals("{")) {
stack--;
end = i;// skip it;
}
}
if (hit == false) {
// TODO: find the type in the class members and super class members
}
// TODO: find full class name in the java.lang.* or in the header of the source
// of import section.
}
private static boolean findInScope(String source, String id, int start, int end) {
String regex = "[A-Za-z0-9_$]+\\s+" + id;
String text = source.substring(start, end);
Matcher matcher = Pattern.compile(regex).matcher(text);
boolean result = matcher.find();
if (result) {
hitString = matcher.group();
System.err.println("hitString = " + hitString + " ,in the text scope: " + text);
}
return result;
}
private static boolean luckFindInScope(String source, String id) {
String regex = "[A-Za-z0-9_$]+\\s+" + id;
Matcher matcher = Pattern.compile(regex).matcher(source);
int count = 0;
while (matcher.find()) {
count++;
hitString= matcher.group();
}
return count == 1;
}
private static String hitString = "";
// fill star * in the string value
private static String removeStringInSource(String input) {
Matcher matcher = Pattern.compile("\".*?\"").matcher(input);
String match = "";
while(matcher.find()) {
match = matcher.group();
char[] symbols = new char[match.length()];
Arrays.fill(symbols, '*');
input = input.replace(match, new String(symbols));
}
System.out.println("$$ removed: " + input);
return input;
}
}
package com.mytest.test.parse;
public class TestFile {
public static void main(String[] args) {
String sample = "foo bar";
System.out.println(sample.length());
}
public static String sample = null;
public static void test1() {
if (sample != null) {
{
String sample = "foo bar";
System.out.println(sample);
{
sample = "foo bar";
System.out.println(sample);
}
}
{
System.out.println(sample);
int test = 0;
{
if (test >= 0) {
sample = "foo bar";
System.out.println(sample);
String sample = "foo bar";
System.out.println(sample);
}
}
}
if(sample.equals("foo bar")) {
System.out.println(sample);
}
}
if( sample == null) {
String sample = "foo bar";
if(sample.equals("foo bar")) {
System.out.println(sample);
}
}
}
public static void test2{
if( sample == null) {
String sample = "foo bar";
if(sample.equals("foo bar")) {
System.out.println(sample);
}
}
}
}
package com.mytest.core.share;
import java.io.File;
import java.io.FileInputStream;
import java.util.Arrays;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.io.IOUtils;
public class TestParse {
public static void main(String[] args) throws Exception {
//testHit();
testNotHit();
}
public static void testNotHit() throws Exception {
// input position
int position = 511;
String id = "sample";
parse(position, id);
}
public static void testHit() throws Exception {
// input position
int position = 955;
String id = "sample";
parse(position, id);
}
public static void parse(int position, String id) throws Exception {
int end = position;
FileInputStream fs = new FileInputStream(new File("TestFile.java"));
String source = IOUtils.toString(fs, "UTF-8");
source = source.substring(0, end);
System.out.println("### look from" +source);
// remove all String in source code;
source = removeStringInSource(source);
int start = 0;
int stack = 0;// for nested scope
boolean hit = false;
// find the char '{' from the end of source
for (int i = source.length(); i > 0; i--) {
String current = source.substring(i - 1, i);
if (stack == 0) {
if (current.equals("{")) {
start = i;// lookup from start to end;
System.err.println("from this {, start to search from the location at " + i);
hit = findInScope(source, id, start, end);
end = start; // skip, search next scope;
if (hit) {
break;
} else {
continue;
}
}
}
// skip bracket pair {}
if (current.equals("}")) {
stack++;
end = i;// skip it;
}
if (current.equals("{")) {
stack--;
end = i;// skip it;
}
}
if (hit == false) {
// TODO: find the type in the class members and super class members
}
// TODO: find full class name in the java.lang.* or in the header of the source
// of import section.
}
private static boolean findInScope(String source, String id, int start, int end) {
String regex = "[A-Za-z0-9_$]+\\s+" + id;
String text = source.substring(start, end);
Matcher matcher = Pattern.compile(regex).matcher(text);
boolean result = matcher.find();
if (result) {
hitString = matcher.group();
System.err.println("hitString = " + hitString + " ,in the text scope: " + text);
}
return result;
}
private static boolean luckFindInScope(String source, String id) {
String regex = "[A-Za-z0-9_$]+\\s+" + id;
Matcher matcher = Pattern.compile(regex).matcher(source);
int count = 0;
while (matcher.find()) {
count++;
hitString= matcher.group();
}
return count == 1;
}
private static String hitString = "";
// fill star * in the string value
private static String removeStringInSource(String input) {
Matcher matcher = Pattern.compile("\".*?\"").matcher(input);
String match = "";
while(matcher.find()) {
match = matcher.group();
char[] symbols = new char[match.length()];
Arrays.fill(symbols, '*');
input = input.replace(match, new String(symbols));
}
System.out.println("$$ removed: " + input);
return input;
}
}
package com.mytest.test.parse;
public class TestFile {
public static void main(String[] args) {
String sample = "foo bar";
System.out.println(sample.length());
}
public static String sample = null;
public static void test1() {
if (sample != null) {
{
String sample = "foo bar";
System.out.println(sample);
{
sample = "foo bar";
System.out.println(sample);
}
}
{
System.out.println(sample);
int test = 0;
{
if (test >= 0) {
sample = "foo bar";
System.out.println(sample);
String sample = "foo bar";
System.out.println(sample);
}
}
}
if(sample.equals("foo bar")) {
System.out.println(sample);
}
}
if( sample == null) {
String sample = "foo bar";
if(sample.equals("foo bar")) {
System.out.println(sample);
}
}
}
public static void test2{
if( sample == null) {
String sample = "foo bar";
if(sample.equals("foo bar")) {
System.out.println(sample);
}
}
}
}
如果我理解您的问题，您要求将原始文本解析为代码。这不是一个小问题——您是否尝试过编写代码来实现这一点？如果是这样的话，请把它贴在你遇到麻烦的地方。你真的需要把java源代码当作原始文本吗？如果您愿意不支持局部变量，我将使用反射来实现这一点，这要简单得多。请看这里：您需要确定变量在代码中声明的位置，然后提取其类型的名称，然后计算该名称所指的类型。总而言之，绝对不是小事。当然，您可以使用编译器API，但我甚至不能说这使它特别容易。@ggorlen我还没有尝试过任何东西。我正在考虑解决办法。如果我在实现它时遇到麻烦，我会发布一些东西。@MarDev是的，我需要将java源代码视为原始文本，反射对我不起作用：（如果我理解你的问题，你是在要求将原始文本解析为代码。这不是一个小问题——你是否尝试过编写任何代码来实现这一点？如果是，请将其与遇到问题的区域一起发布。你真的需要将java源代码视为原始文本吗？如果你没有打开，我会对此使用反射，更简单o不支持局部变量。请参见此处：您需要确定变量在代码中声明的位置，然后提取其类型的名称，然后确定该名称所指的类型。总之，这绝对不是一件小事。当然，您可以使用编译器API，但我甚至不认为这使它特别容易。@ggorlen我没有尝试过任何东西。正在考虑解决方案。如果我在实现它时遇到问题，我会发布一些东西。@MarDev是的，我需要将java源代码视为原始文本，反射对我不起作用：（这看起来很有希望。我现在将在我的计算机上运行此代码。如果它解决了我提到的问题，我将接受它作为答案。这看起来很有希望。我现在将在我的计算机上运行此代码。如果它解决了我提到的问题，我将接受它作为答案。