com.google.gson.JsonSyntaxException：预期为字符串，但为 BEGIN_ARRAY答案

【问题标题】：com.google.gson.JsonSyntaxException:Expected STRING but was BEGIN_ARRAYcom.google.gson.JsonSyntaxException：预期为字符串，但为 BEGIN_ARRAY
【发布时间】：2017-08-18 06:00:46
【问题描述】：

请帮我获取 bom 属性中的子节点列表

JSON 文件

[  
 {  
  "subConfigId":"bac",
  "totalPrice":"634.00",
  "bom":{  
     "ucid":"ucid",
     "type":"RootNode",
     "attributes":{  
        "visible":true,
        "price_status":"SUCCESS"
     },
     "subnodes":[  
        {  
           "description":"Enterprise Shock Rack",
           "ucid":"ucid"
        },
        {  
           "description":"SVC",
           "ucid":"ucid"
        }
     ]
  },
  "breakdown":{  
     "SV":550.0,
     "HW":6084.0
  },
  "currency":"USD"
 }
]

GsonNodes.java

 import java.io.FileReader;
 import java.io.IOException;
 import java.util.Iterator;
 import com.google.gson.Gson;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonParser;

  public class GsonNodes {
  public static void main(String[] args) throws IOException {   

    try{                 
     JsonElement je = new JsonParser().parse(new FileReader(
             "C:/Desktop/json.txt"));
     JsonArray ja = je.getAsJsonArray();
     Iterator itr = ja.iterator();

     while(itr.hasNext()){
         JsonElement je1 = (JsonElement) itr.next();
         Gson gson = new Gson();
         Details details = gson.fromJson(je1, Details.class);          

         System.out.println(details.getSubConfigId());
         System.out.println(details.getCurrency());
         System.out.println(details.getBreakdown());
         System.out.println(details.getTotalPrice());
         System.out.println(details.getBom().getUcid());         

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

Details.java POJO

    import java.io.Serializable;
    import java.util.Map;
    public class Details implements Serializable{

        private String subConfigId;
        private String totalPrice;
        private Bom bom;     
        private String currency;
        private Map<String, String> breakdown;

        public String getSubConfigId() {
            return subConfigId;
        }
        public void setSubConfigId(String subConfigId) {
            this.subConfigId = subConfigId;
        }
        public String getTotalPrice() {
            return totalPrice;
        }
        public void setTotalPrice(String totalPrice) {
            this.totalPrice = totalPrice;
        }
        public Bom getBom() {
            return bom;
        }
        public void setBom(Bom bom) {
            this.bom = bom;
        }
        public String getCurrency() {
            return currency;
        }
        public void setCurrency(String currency) {
            this.currency = currency;
        }
        public Map<String, String> getBreakdown() {
            return breakdown;
        }
        public void setBreakdown(Map<String, String> breakdown) {
            this.breakdown = breakdown;
        }
    }

Bom.java

    import java.io.Serializable;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;

    public class Bom implements Serializable{

        private String ucid;
        private String type;
        private Map<String, String> attributes;
        private List<Subnodes> subnodes = new ArrayList<Subnodes>();  

        public String getUcid() {
            return ucid;
        }
        public void setUcid(String ucid) {
            this.ucid = ucid;
        }
        public String getType() {
            return type;
        }
        public void setType(String type) {
            this.type = type;
        }
        public Map<String, String> getAttributes() {
            return attributes;
        }
        public void setAttributes(Map<String, String> attributes) {
            this.attributes = attributes;
        }   

        @Override
        public String toString(){
            return getUcid() + ", "+getType()+", "+getAttributes();
        }

    }

子节点.java

    import java.io.Serializable;
    import java.util.Map;

    public class Subnodes implements Serializable{

        private String description;
        private String ucid;
        private Map<String, String> attributes;

        public String getDescription() {
            return description;
        }
        public void setDescription(String description) {
            this.description = description;
        }
        public String getUcid() {
            return ucid;
        }
        public void setUcid(String ucid) {
            this.ucid = ucid;
        }
        public Map<String, String> getAttributes() {
            return attributes;
        }
        public void setAttributes(Map<String, String> attributes) {
            this.attributes = attributes;
        }   
    }

当我尝试获取“子节点”时出现错误我在类中添加了以下代码

  private List<Subnodes> subnodes = new ArrayList<Subnodes>();

然后我收到错误“预期为字符串，但为 BEGIN_ARRAY”

请帮助我如何获取“子节点”列表

【问题讨论】：

标签： java parsing exception gson pojo

【解决方案1】：

在 Bom.java 中

请添加 getter/setter 方法：

private List<Subnodes> subnodes = new ArrayList<Subnodes>();

public List<Subnodes> getSubnodes() {
    return subnodes;
}

public void setSubnodes(List<Subnodes> subnodes) {
    this.subnodes = subnodes;
}

我已经尝试如下..这工作正常。

package com.brp.mvc.util;

import java.io.IOException;
import java.util.Iterator;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonParser;

public class GsonNodes {
    public static void main(String[] args) throws IOException {

        try {
            JsonElement je = new JsonParser().parse("[{\"subConfigId\":\"bac\",\"totalPrice\":\"634.00\",\"bom\":{\"ucid\":\"ucid\",\"type\":\"RootNode\",\"attributes\":{\"visible\":true,\"price_status\":\"SUCCESS\"},\"subnodes\":[{\"description\":\"Enterprise Shock Rack\",\"ucid\":\"ucid\"},{\"description\":\"SVC\",\"ucid\":\"ucid\"}]},\"breakdown\":{\"SV\":550.0,\"HW\":6084.0},\"currency\":\"USD\"}]");
            JsonArray ja = je.getAsJsonArray();
            Iterator itr = ja.iterator();

            while (itr.hasNext()) {
                JsonElement je1 = (JsonElement) itr.next();
                Gson gson = new Gson();
                Details details = gson.fromJson(je1, Details.class);

                System.out.println(details.getSubConfigId());
                System.out.println(details.getCurrency());
                System.out.println(details.getBreakdown());
                System.out.println(details.getTotalPrice());
                System.out.println(details.getBom().getUcid());
                System.out.println(details.getBom().getSubnodes().get(0).getDescription());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

【讨论】：

我尝试过，但出现以下错误 java.lang.IllegalStateException: Expected STRING but was BEGIN_ARRAY at com.google.gson.internal.bind.JsonTreeReader.nextString(JsonTreeReader.java:154)com。 google.gson.internal.bind.TypeAdapters$13.read(TypeAdapters.java:349)
你能分享完整的stackTrace吗？
感谢 patel.. 如何像这样转换 "[{\"subConfigId\":\"bac\",\"totalPrice\""
无需转换为字符串 .. 它也可以像您一样使用 json 文件。它可能是依赖问题......我在依赖下面使用.. com.google.code.gsongson2.1
它也可能文件问题..请尝试创建新的json文件

【解决方案2】：

我添加了一种将 json 转换为字符串的方法，如下所示：

    public static String readFile(String filename) {
        String result = "";
        try {
            BufferedReader br = new BufferedReader(new FileReader(filename));
            StringBuilder sb = new StringBuilder();
            String line = br.readLine();
            while (line != null) {
                sb.append(line);
                line = br.readLine();
            }
            result = sb.toString();
        } catch(Exception e) {
            e.printStackTrace();
        }
        return result;
    }

并使用如下方法：

            JsonElement je = new JsonParser().parse(readFile("C:/Desktop/json.txt"));

【讨论】：