有时为了项目需求，会将对象数据转换成json数据，以下是个人根据项目需求实现的方法。
项目中需要将数据格式：
[{
"node": "0",
"index": null,
"status": null,
"preNode": null,
"postNode": [{
"node": "xxx_4"
},
{
"node": "xxx_3"
},
{
"node": "xxx_2"
},
{
"node": "xxx_14"
}]
},
{
"node": "xxx_2",
"index": "index_1",
"status": "表达式1",
"preNode": [{
"node": "xxx_0"
}],
"postNode": [{
"node": "xxx_5"
}]
},
{
"node": "xxx_14",
"index": "index_4",
"status": "表达式5",
"preNode": [{
"node": "xxx_0"
}],
"postNode": [{
"node": "xxx_13"
},
{
"node": "xxx_5"
}]
},
{
"node": "xxx_3",
"index": "index_2",
"status": "表达式2",
"preNode": [{
"node": "xxx_0"
}],
"postNode": [{
"node": "xxx_5"
}]
},
{
"node": "xxx_4",
"index": "index_3",
"status": "表达式3",
"preNode": [{
"node": "xxx_0"
}],
"postNode": [{
"node": "xxx_12"
}]
},
{
"node": "xxx_5",
"index": "index_4",
"status": "表达式4",
"preNode": [{
"node": "xxx_3"
},
{
"node": "xxx_2"
},
{
"node": "xxx_14"
}],
"postNode": [{
"node": "xxx_6"
}]
},
{
"node": "xxx_6",
"index": "index_5",
"status": "表达式6",
"preNode": [{
"node": "xxx_5"
}],
"postNode": [{
"node": "xxx_7"
}]
},
{
"node": "xxx_7",
"index": "index_6",
"status": "表达式7",
"preNode": [{
"node": "xxx_6"
}],
"postNode": [{
"node": "xxx_8"
}]
},
{
"node": "xxx_8",
"index": "index_4",
"status": "表达式8",
"preNode": [{
"node": "xxx_7"
}],
"postNode": [{
"node": "xxx_9"
},
{
"node": "xxx_10"
}]
},
{
"node": "xxx_9",
"index": "index_5",
"status": "表达式5",
"preNode": [{
"node": "xxx_8"
}],
"postNode": [{
"node": "xxx_11"
}]
},
{
"node": "xxx_10",
"index": "index_7",
"status": "表达式6",
"preNode": [{
"node": "xxx_8"
}],
"postNode": [{
"node": "xxx_11"
}]
},
{
"node": "xxx_11",
"index": "index_8",
"status": "表达式7",
"preNode": [{
"node": "xxx_9"
},
{
"node": "xxx_10"
}],
"postNode": [{
"node": "xxx_12"
}]
},
{
"node": "xxx_12",
"index": "index_8",
"status": "表达式7",
"preNode": [{
"node": "xxx_11"
},
{
"node": "xxx_4"
}],
"postNode": [{
"node": "xxx_13"
}]
},
{
"node": "xxx_13",
"index": "",
"status": "",
"preNode": [{
"node": "xxx_14"
},
{
"node": "xxx_12"
}],
"postNode": []
},
{
"node": "9999",
"index": null,
"status": null,
"preNode": [{
"node": "xxx_14"
},
{
"node": "xxx_12"
}],
"postNode": null
}]
项目中list对象内容
JsonModel{node='xxx_2', preNode='', index='index_1', status='表达式1'}
JsonModel{node='xxx_14', preNode='', index='index_4', status='表达式5'}
JsonModel{node='xxx_3', preNode='', index='index_2', status='表达式2'}
JsonModel{node='xxx_4', preNode='', index='index_3', status='表达式3'}
JsonModel{node='xxx_5', preNode='xxx_2', index='index_4', status='表达式4'}
JsonModel{node='xxx_5', preNode='xxx_3', index='index_4', status='表达式5'}
JsonModel{node='xxx_5', preNode='xxx_14', index='index_4', status='表达式5'}
JsonModel{node='xxx_6', preNode='xxx_5', index='index_5', status='表达式6'}
JsonModel{node='xxx_7', preNode='xxx_6', index='index_6', status='表达式7'}
JsonModel{node='xxx_8', preNode='xxx_7', index='index_4', status='表达式8'}
JsonModel{node='xxx_9', preNode='xxx_8', index='index_5', status='表达式5'}
JsonModel{node='xxx_10', preNode='xxx_8', index='index_7', status='表达式6'}
JsonModel{node='xxx_11', preNode='xxx_10', index='index_8', status='表达式7'}
JsonModel{node='xxx_11', preNode='xxx_9', index='index_8', status='表达式8'}
JsonModel{node='xxx_12', preNode='xxx_11', index='index_8', status='表达式7'}
JsonModel{node='xxx_12', preNode='xxx_4', index='index_8', status='表达式8'}
JsonModel{node='xxx_13', preNode='xxx_14', index='', status='表达式13'}
JsonModel{node='xxx_13', preNode='xxx_12', index='', status='表达式14'}
public void testJson() throws Exception{
List<JsonModel> list=new ArrayList<>();
ObjectMapper objectMapper=new ObjectMapper();
JsonModel jsonModel=new JsonModel("xxx_2","","index_1","表达式1");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_14","","index_4","表达式5");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_3","","index_2","表达式2");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_4","","index_3","表达式3");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_5","xxx_2","index_4","表达式4");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_5","xxx_3","index_4","表达式5");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_5","xxx_14","index_4","表达式5");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_6","xxx_5","index_5","表达式6");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_7","xxx_6","index_6","表达式7");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_8","xxx_7","index_4","表达式8");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_9","xxx_8","index_5","表达式5");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_10","xxx_8","index_7","表达式6");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_11","xxx_10","index_8","表达式7");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_11","xxx_9","index_8","表达式8");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_12","xxx_11","index_8","表达式7");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_12","xxx_4","index_8","表达式8");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_13","xxx_14","","表达式13");
list.add(jsonModel);
jsonModel=new JsonModel("xxx_13","xxx_12","","表达式14");
list.add(jsonModel);
list.forEach(var->
System.out.println(var.toString())
);
System.out.println();
//将list转成String
String str=objectMapper.writeValueAsString(list);
//将字符串转成JsonNode
JsonNode rootNode = objectMapper.readTree(str);
Set<ChildNode> preNode_set=null;
Set<ChildNode> postNode_set=null;
List<Node> nodeList=new ArrayList<>();
//寻找第一个indxe 创建一个start节点
Node node=new Node();
node.setNode("0");
Set<ChildNode> childNodeList=new HashSet<>();
for(int i=0;i<rootNode.size();i++){
if("".equals(rootNode.get(i).get("preNode").asText())){
childNodeList.add(new ChildNode(rootNode.get(i).get("node").asText()));
}
}
node.setPostNode(childNodeList);
nodeList.add(node);
//这种方式在如果我们只需要一个长json串中某个字段值时非常方便
for (int i=0;i<rootNode.size();){
preNode_set=new HashSet<>();
postNode_set=new HashSet<>();
//直接从rootNode中获取某个键的值，
JsonNode nameNode = (rootNode.get(i)).get("node");
String name = nameNode.asText();
String index=rootNode.get(i).get("index").asText();
String status=rootNode.get(i).get("status").asText();
//找出后置节点 post_node
for(int j=i+1;j<rootNode.size();j++){
String names = (rootNode.get(j)).get("preNode").asText();
if(name.equals(names)){
// if(!"".equals(rootNode.get(j).get("postNode").asText())) {
postNode_set.add(new ChildNode((rootNode.get(j)).get("node").asText()));
//}
}
}
//找前置节点
for(int j=0;j<list.size();j++){
String names = (rootNode.get(j)).get("node").asText();
//对于后一个的index相同时 需要跳过
if(name.equals(names)){
if(!"".equals(rootNode.get(j).get("preNode").asText())){
preNode_set.add(new ChildNode((rootNode.get(j)).get("preNode").asText()));
if(j>i){
++i;
}else{
i++;
}
}else{
preNode_set.add(new ChildNode("0"));
i++;
}
}
}
Node nodes=new Node();
nodes.setIndex(index);
nodes.setNode(name);
nodes.setStatus(status);
nodes.setPostNode(postNode_set);
nodes.setPreNode(preNode_set);
nodeList.add(nodes);
}
//后置节点
Node pre_node=new Node();
pre_node.setNode("9999");
Set<ChildNode> childNodes=new HashSet<>();
for(int i=0;i<rootNode.size();i++){
//最后一个end 节点的pre_node
if("".equals(rootNode.get(i).get("index").asText())){
childNodes.add(new ChildNode(rootNode.get(i).get("preNode").asText()));
}
}
pre_node.setPreNode(childNodes);
nodeList.add(pre_node);
String s = objectMapper.writeValueAsString(nodeList);
System.out.println(s);
System.out.println();
jsonTest(s);
}
/**
* <p>json --> 对象</p>
* @param s
* @throws Exception
*/
public void jsonTest(String s) throws Exception{
List<Node> nodeList=new ArrayList<>();
ObjectMapper objectMapper=new ObjectMapper();
//将字符串用objectMapper转换成jsonNode
JsonNode jsonNode=objectMapper.readTree(s);
List<JsonModel> jsonModels=new ArrayList<>();
for(int i=1;i<jsonNode.size()-1;i++){
String index=jsonNode.get(i).get("index").asText();
String status=jsonNode.get(i).get("status").asText();
String node=jsonNode.get(i).get("node").asText();
for(int j=0;j<jsonNode.get(i).get("preNode").size();j++){
String childNode= jsonNode.get(i).get("preNode").get(j).get("node").asText();
JsonModel jsonModel=new JsonModel(node,childNode,index,status);
jsonModels.add(jsonModel);
}
}
jsonModels.forEach(val->
System.out.println(val.toString())
);
}
以下是所用到的对象实体类
package com.yf.af.biz.test;
/**
* Created by chen on 2017/7/14.
*/
public class JsonModel {
private String node;
private String preNode;
private String index;
private String status;
public String getNode() {
return node;
}
public void setNode(String node) {
this.node = node;
}
public String getPreNode() {
return preNode;
}
public void setPreNode(String preNode) {
this.preNode = preNode;
}
public String getIndex() {
return index;
}
public void setIndex(String index) {
this.index = index;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public JsonModel(String node, String preNode, String index, String status) {
this.node = node;
this.preNode = preNode;
this.index = index;
this.status = status;
}
public JsonModel() {
}
@Override
public String toString() {
return "JsonModel{" +
"node='" + node + '\'' +
", preNode='" + preNode + '\'' +
", index='" + index + '\'' +
", status='" + status + '\'' +
'}';
}
}
package com.yf.af.biz.test;
import java.util.List;
import java.util.Set;
/**
* Created by chen on 2017/7/15.
*/
public class Node {
private String node;
private String index;
private String status;
private Set<ChildNode> preNode;
private Set<ChildNode> postNode;
public String getNode() {
return node;
}
public void setNode(String node) {
this.node = node;
}
public String getIndex() {
return index;
}
public void setIndex(String index) {
this.index = index;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public Set<ChildNode> getPreNode() {
return preNode;
}
public void setPreNode(Set<ChildNode> preNode) {
this.preNode = preNode;
}
public Set<ChildNode> getPostNode() {
return postNode;
}
public void setPostNode(Set<ChildNode> postNode) {
this.postNode = postNode;
}
@Override
public String toString() {
return "Node{" +
"node='" + node + '\'' +
", index='" + index + '\'' +
", status='" + status + '\'' +
", preNode=" + preNode +
", postNode=" + postNode +
'}';
}
public Node() {
}
}
package com.yf.af.biz.test;
/**
* Created by chen on 2017/7/15.
*/
public class ChildNode {
private String node;
public String getNode() {
return node;
}
public void setNode(String node) {
this.node = node;
}
public ChildNode(String node) {
this.node = node;
}
public ChildNode() {
}
}