我在从json文件中获取我想要的值时遇到了一些麻烦。我正在使用simple-json。它看起来像这样：
this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
this.Text = "Form title";
this.Load += new System.EventHandler(this.Form_Load);
文件很大，包含大约800个练习。我想要的是映射字符串，例如“强制”，“级别”，但我不确定我将如何访问它。
这是我目前的代码
[
{
"BUTT LIFT (BRIDGE)": [
{
"Main Muscle Worked": "Glutes",
"Sport": "No",
"Force": "Push",
"Level": "Beginner",
"mucle_heatmap": "http://assets.bodybuilding.com/images/trackers/exercise/heatmap/14.gif",
"female_image_end": "http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Female/l/99_2.jpg",
"female_image_start": "http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Female/l/99_1.jpg",
"guide": [
"Lie flat on the floor on your back with the hands by your side and your knees bent. Your feet should be placed around shoulder width. This will be your starting position.",
"Pushing mainly with your heels, lift your hips off the floor while keeping your back straight. Breathe out as you perform this part of the motion and hold at the top for a second.",
"Slowly go back to the starting position as you breathe in."
],
"male_image_start": "http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Male/l/99_1.jpg",
"Equipment": "Body Only",
"link": "http://www.bodybuilding.com/exercises/detail/view/name/butt-lift-bridge",
"male_image_end": "http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Male/l/99_2.jpg",
"Other Muscles": "Hamstrings",
"Type": "Strength",
"Mechanics Type": "Isolation"
}
]
},
这导致获取整个JSON文件。
答案 0 :(得分：0)
使用json-simple递归地传递JSON并不困难。在这里，我只关注String和Long字段，但很明显如何添加更多字段。
public class WalkJSON {
private static final String PATH_SEPARATOR = "/";
/**
* Offers the opportunity to examine fields in the JSON.
*/
public static class FieldVisitor {
void visit(String path, String value){};
void visit(String path, Long value){};
}
/**
* Walks the JSON structure calling the visitor for every String field in the structure.
*/
public static void walk(String jsonString, FieldVisitor visitor) throws ParseException {
walk(new JSONParser().parse(jsonString), "", visitor);
}
/**
* Discerns which type of object it is and dispatches to the correct method.
*/
private static void walk(Object json, String path, FieldVisitor visitor) {
if (json instanceof JSONObject) {
walk((JSONObject) json, path, visitor);
} else if (json instanceof JSONArray) {
walk((JSONArray) json, path, visitor);
} else if (json instanceof String) {
visitor.visit(path, (String) json);
} else if (json instanceof Long) {
visitor.visit(path, (Long) json);
} else {
System.out.println("Unknown type "+json.getClass());
}
}
/**
* Walks all keys of a JSONObject.
*/
private static void walk(JSONObject json, String path, FieldVisitor visitor) {
for (Object o : json.entrySet()) {
Map.Entry<String, Object> e = (Map.Entry<String, Object>) o;
// Visit every entry.
walk(e.getValue(), path + PATH_SEPARATOR + e.getKey(), visitor);
}
}
/**
* Walks all entries in a JSON array.
*/
private static void walk(JSONArray json, String path, FieldVisitor visitor) {
for (int i = 0; i < json.size(); i++) {
// Visit every entry.
walk(json.get(i), path + PATH_SEPARATOR + i, visitor);
}
}
}
然后，您可以编写自己的访问者以捕获特定字段。
WalkJSON.walk(json, new WalkJSON.FieldVisitor() {
@Override
public void visit(String path, String value) {
if(path.contains("/guide/")) {
System.out.println(value);
}
}
});
您现在需要做的就是找出如何使用正则表达式或其他内容选择要查找的字段。
答案 1 :(得分：0)
我在这里使用org.json。通过考虑您的输入JSON和您给出的逗号,的位置，我假设"BUTT LIFT (BRIDGE)"将始终具有一个元素。如果它的元素多于1，我们将不得不为BUTT LIFT (BRIDGE)编写另一个内部循环。
package org.home.example;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONObject;
public class Test {
public static void main(String[] args) {
//input arry with with two elements. It can have more elements
String StringJson="[{\"BUTT LIFT (BRIDGE)\":[{\"Main Muscle Worked\":\"Glutes\",\"Sport\":\"No\",\"Force\":\"Push\",\"Level\":\"Beginner\",\"mucle_heatmap\":\"http://assets.bodybuilding.com/images/trackers/exercise/heatmap/14.gif\",\"female_image_end\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Female/l/99_2.jpg\",\"female_image_start\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Female/l/99_1.jpg\",\"guide\":[\"Lie flat on the floor on your back with the hands by your side and your knees bent. Your feet should be placed around shoulder width. This will be your starting position.\",\"Pushing mainly with your heels, lift your hips off the floor while keeping your back straight. Breathe out as you perform this part of the motion and hold at the top for a second.\",\"Slowly go back to the starting position as you breathe in.\"],\"male_image_start\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Male/l/99_1.jpg\",\"Equipment\":\"Body Only\",\"link\":\"http://www.bodybuilding.com/exercises/detail/view/name/butt-lift-bridge\",\"male_image_end\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Male/l/99_2.jpg\",\"Other Muscles\":\"Hamstrings\",\"Type\":\"Strength\",\"Mechanics Type\":\"Isolation\"}]},{\"BUTT LIFT (BRIDGE)\":[{\"Main Muscle Worked\":\"Glutes\",\"Sport\":\"No\",\"Force\":\"Push1\",\"Level\":\"Beginner1\",\"mucle_heatmap\":\"http://assets.bodybuilding.com/images/trackers/exercise/heatmap/14.gif\",\"female_image_end\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Female/l/99_2.jpg\",\"female_image_start\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Female/l/99_1.jpg\",\"guide\":[\"Lie flat on the floor on your back with the hands by your side and your knees bent. Your feet should be placed around shoulder width. This will be your starting position.\",\"Pushing mainly with your heels, lift your hips off the floor while keeping your back straight. Breathe out as you perform this part of the motion and hold at the top for a second.\",\"Slowly go back to the starting position as you breathe in.\"],\"male_image_start\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Male/l/99_1.jpg\",\"Equipment\":\"Body Only\",\"link\":\"http://www.bodybuilding.com/exercises/detail/view/name/butt-lift-bridge\",\"male_image_end\":\"http://www.bodybuilding.com/exercises/exerciseImages/sequences/99/Male/l/99_2.jpg\",\"Other Muscles\":\"Hamstrings\",\"Type\":\"Strength\",\"Mechanics Type\":\"Isolation\"}]}]";
JSONArray object=new JSONArray(StringJson);
HashMap<Integer,String> Force=new HashMap<Integer,String>();
HashMap<Integer,String> Level=new HashMap<Integer,String>();
//iterate the array
for(int i=0;i<object.length();i++){
JSONObject parts=object.getJSONObject(i).getJSONArray("BUTT LIFT (BRIDGE)").getJSONObject(0);
Force.put(i, parts.getString("Force"));
Level.put(i,parts.getString("Level"));
}
System.out.println("Force map");
for (HashMap.Entry<Integer, String> entry : Force.entrySet())
{
System.out.println(entry.getKey() + "/" + entry.getValue());
}
System.out.println("Level map");
for (HashMap.Entry<Integer, String> entry : Level.entrySet())
{
System.out.println(entry.getKey() + "/" + entry.getValue());
}
}
}