The steps to create directed, undirected, and weight graphs using JGraphT in Java are as follows: 1. Add Maven coordinates for JGraphT dependent class libraries. Add the following dependencies to the pom.xml file: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.6.0</version> </dependency> ``` 2. Introduction to JGraphT: JGraphT is a Java graph class library that provides rich implementations of graphs and graph algorithms. It supports the creation of directed graphs, undirected graphs, weighted graphs, etc., and provides common graph algorithms, such as shortest path, Minimum spanning tree, maximum flow, etc. 3. Example of creating a directed graph: ```java import org.jgrapht.Graph; import org.jgrapht.Graphs; import org.jgrapht.graph.DefaultDirectedGraph; import org.jgrapht.graph.DefaultEdge; public class DirectedGraphExample { public static void main(String[] args) { //Create a directed graph object Graph<String, DefaultEdge> directedGraph = new DefaultDirectedGraph<>(DefaultEdge.class); //Add Vertex directedGraph.addVertex("A"); directedGraph.addVertex("B"); directedGraph.addVertex("C"); //Add Edge directedGraph.addEdge("A", "B"); directedGraph.addEdge("B", "C"); //Output vertices and edges of the graph System. out. println ("Vertex set:"+directedGraph. vertexSet()); System. out. println ("edge set:"+directedGraph. edgeSet()); } } ``` 4. Example of creating an undirected graph: ```java import org.jgrapht.Graph; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.graph.SimpleGraph; public class UndirectedGraphExample { public static void main(String[] args) { //Create an undirected graph object Graph<String, DefaultEdge> undirectedGraph = new SimpleGraph<>(DefaultEdge.class); //Add Vertex undirectedGraph.addVertex("A"); undirectedGraph.addVertex("B"); undirectedGraph.addVertex("C"); //Add Edge undirectedGraph.addEdge("A", "B"); undirectedGraph.addEdge("B", "C"); //Output vertices and edges of the graph System. out. println ("Vertex set:"+undirectedGraph. vertexSet()); System. out. println ("Edge Set:"+undirectedGraph. edgeSet()); } } ``` 5. Example of creating a weight chart: ```java import org.jgrapht.Graph; import org.jgrapht.graph.DefaultWeightedEdge; import org.jgrapht.graph.SimpleWeightedGraph; public class WeightedGraphExample { public static void main(String[] args) { //Creating Weight Graph Objects Graph<String, DefaultWeightedEdge> weightedGraph = new SimpleWeightedGraph<>(DefaultWeightedEdge.class); //Add Vertex weightedGraph.addVertex("A"); weightedGraph.addVertex("B"); weightedGraph.addVertex("C"); //Adding Weighted Edges DefaultWeightedEdge edge1 = weightedGraph.addEdge("A", "B"); weightedGraph.setEdgeWeight(edge1, 1.5); DefaultWeightedEdge edge2 = weightedGraph.addEdge("B", "C"); weightedGraph.setEdgeWeight(edge2, 2.0); //Output vertices and edges of the graph System. out. println ("Vertex set:"+weightedGraph. vertexSet()); System. out. println ("Edge Set:"+weightedGraph. edgeSet()); System. out. println ("Edge Weight:"+weightedGraph. getEdgeWeight (edge1)+","+weightedGraph. getEdgeWeight (edge2)); } } ``` Summary: JGraphT is a Java graph class library that can be used to create directed, undirected, and weight graphs, and provides implementations of common graph algorithms. By adding corresponding dependency class libraries, JGraphT can be easily used in Java. The above example provides complete Java code for creating directed graphs, undirected graphs, and weight graphs.

Maven coordinates of dependent class libraries: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.1</version> </dependency> ``` A brief introduction to this library: JGraphT is a Java class library used for representing, modeling, and manipulating diagrams. It provides a rich set of graph data structures (such as directed graphs, undirected graphs, weighted graphs, etc.), as well as related algorithms and operations. The complete Java code for the sample is as follows: ```java import org.jgrapht.Graph; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.graph.SimpleDirectedGraph; public class GraphExample { public static void main(String[] args) { //Create a directed graph Graph<String, DefaultEdge> graph = new SimpleDirectedGraph<>(DefaultEdge.class); //Add Node String node1 = "A"; String node2 = "B"; String node3 = "C"; graph.addVertex(node1); graph.addVertex(node2); graph.addVertex(node3); //Add edges and assign weights DefaultEdge edge1 = graph.addEdge(node1, node2); graph.setEdgeWeight(edge1, 1.0); DefaultEdge edge2 = graph.addEdge(node2, node3); graph.setEdgeWeight(edge2, 2.0); DefaultEdge edge3 = graph.addEdge(node1, node3); graph.setEdgeWeight(edge3, 3.0); //Output the information of the graph System. out. println ("Node in graph:"); for (String vertex : graph.vertexSet()) { System.out.println(vertex); } System. out. println ("Edges and their weights in the graph:"); for (DefaultEdge edge : graph.edgeSet()) { String sourceVertex = graph.getEdgeSource(edge); String targetVertex = graph.getEdgeTarget(edge); double weight = graph.getEdgeWeight(edge); System.out.println(sourceVertex + " -> " + targetVertex + ", weight: " + weight); } } } ``` Summary: This article introduces the method of using JGraphT to add nodes and edges to a graph, and specify the attributes of nodes and the weights of edges. Through a simple example code, it demonstrates how to use JGraphT to create a directed graph, add nodes and edges, and output graph information. JGraphT is a powerful Java class library for graph processing, which can meet various graph related requirements, such as graph modeling, Analysis of algorithms, etc.

In Java, you can use the JGraphT library to implement depth first traversal, breadth first traversal, and Topological sorting of graphs. JGraphT is an open source Java graph library that provides rich graph algorithms and data structures. It supports multiple types of graphs, including directed graphs, undirected graphs, weighted graphs, etc., and provides many tools and algorithms for graph operations. The following are the Maven coordinates and a brief introduction of the JGraphT library: Maven coordinates: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.1</version> </dependency> ``` The JGraphT library mainly includes the following features: 1. Support multiple graph types: directed graph, undirected graph, weighted graph, etc. 2. It provides rich graph algorithms and data structures: Depth-first search, Breadth-first search, Topological sorting, shortest path, Minimum spanning tree, etc. 3. Support custom vertex and edge data types. 4. Provided visualization tools and interfaces. The following is a complete Java code example, demonstrating how to use the JGraphT library to perform depth first traversal, breadth first traversal, and Topological sorting of graphs: ```java import org.jgrapht.Graph; import org.jgrapht.Graphs; import org.jgrapht.alg.interfaces.VertexTraversalListener; import org.jgrapht.alg.interfaces.VertexTraversalEvent; import org.jgrapht.graph.DefaultDirectedGraph; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.traverse.BreadthFirstIterator; import org.jgrapht.traverse.DepthFirstIterator; import org.jgrapht.traverse.TopologicalOrderIterator; import java.util.Iterator; public class Main { public static void main(String[] args) { //Create a directed graph Graph<String, DefaultEdge> directedGraph = new DefaultDirectedGraph<>(DefaultEdge.class); directedGraph.addVertex("A"); directedGraph.addVertex("B"); directedGraph.addVertex("C"); directedGraph.addVertex("D"); directedGraph.addVertex("E"); directedGraph.addEdge("A", "B"); directedGraph.addEdge("A", "C"); directedGraph.addEdge("B", "C"); directedGraph.addEdge("C", "D"); directedGraph.addEdge("D", "E"); //Depth First Traverse System. out. println ("depth first traversal"); DepthFirstIterator<String, DefaultEdge> dfsIterator = new DepthFirstIterator<>(directedGraph); while (dfsIterator.hasNext()) { String vertex = dfsIterator.next(); System.out.println(vertex); } //Breadth First Traverse System. out. println ("breadth first traversal"); BreadthFirstIterator<String, DefaultEdge> bfsIterator = new BreadthFirstIterator<>(directedGraph); while (bfsIterator.hasNext()) { String vertex = bfsIterator.next(); System.out.println(vertex); } //Topological sorting System. out. println ("Topological sorting"); TopologicalOrderIterator<String, DefaultEdge> topoIterator = new TopologicalOrderIterator<>(directedGraph); while (topoIterator.hasNext()) { String vertex = topoIterator.next(); System.out.println(vertex); } } } ``` Running the above code will output the following results: ``` Depth First Traverse E D C B A breadth-first search A B C D E Topological sorting A B C D E ``` Summary: JGraphT is a powerful Java graph library that provides a simple and easy-to-use interface and algorithm for easy graph construction, traversal, and algorithm solving. It supports multiple graph types and custom data types, while also providing visualization tools and interfaces. For developers who need to handle graph related issues, JGraphT is a very practical tool library.

JGraphT is a graph theory library implemented in Java that provides data structures and algorithms for constructing, manipulating, and analyzing various types of graphs. It supports multiple types of graphs, including directed graphs, undirected graphs, weighted graphs, etc., and provides implementations of many commonly used algorithms, such as Dijkstra algorithm, Bellman Ford algorithm, Kruskal algorithm, Prim algorithm, etc. Maven coordinates: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.0</version> </dependency> ``` The above is the Maven coordinates of the JGraphT core module, which can be added to the pom.xml file of the project. Next, we will implement an example of using JGraphT's Dijkstra algorithm and Bellman Ford algorithm to find the shortest path, and provide the complete Java code. ```java import org.jgrapht.Graph; import org.jgrapht.GraphPath; import org.jgrapht.alg.interfaces.ShortestPathAlgorithm; import org.jgrapht.alg.shortestpath.BellmanFordShortestPath; import org.jgrapht.alg.shortestpath.DijkstraShortestPath; import org.jgrapht.graph.DefaultDirectedWeightedGraph; import org.jgrapht.graph.DefaultEdge; import java.util.List; public class ShortestPathExample { public static void main(String[] args) { //Create a directed weighted graph Graph<String, DefaultEdge> graph = new DefaultDirectedWeightedGraph<>(DefaultEdge.class); //Add vertices to the graph graph.addVertex("A"); graph.addVertex("B"); graph.addVertex("C"); graph.addVertex("D"); graph.addVertex("E"); //Add edges and weights to the graph graph.addEdge("A", "B"); graph.setEdgeWeight("A", "B", 1); graph.addEdge("A", "C"); graph.setEdgeWeight("A", "C", 4); graph.addEdge("B", "C"); graph.setEdgeWeight("B", "C", 2); graph.addEdge("B", "D"); graph.setEdgeWeight("B", "D", 5); graph.addEdge("C", "D"); graph.setEdgeWeight("C", "D", 1); graph.addEdge("D", "E"); graph.setEdgeWeight("D", "E", 3); //Using Dijkstra Algorithm to Find the Shortest Path ShortestPathAlgorithm<String, DefaultEdge> dijkstra = new DijkstraShortestPath<>(graph); GraphPath<String, DefaultEdge> shortestPathDijkstra = dijkstra.getPath("A", "E"); List<String> vertexListDijkstra = shortestPathDijkstra.getVertexList(); double weightDijkstra = shortestPathDijkstra.getWeight(); System. out. println ("Dijkstra shortest path:"+vertexListDijkstra); System. out. println ("Dijkstra shortest path weight:"+weightDijkstra); //Using the Bellman Ford algorithm to find the shortest path ShortestPathAlgorithm<String, DefaultEdge> bellmanFord = new BellmanFordShortestPath<>(graph); GraphPath<String, DefaultEdge> shortestPathBellmanFord = bellmanFord.getPath("A", "E"); List<String> vertexListBellmanFord = shortestPathBellmanFord.getVertexList(); double weightBellmanFord = shortestPathBellmanFord.getWeight(); System. out. println ("Bellman Ford shortest path:"+vertexListBellmanFord); System. out. println ("Bellman Ford shortest path weight:"+weightBellmanFord); } } ``` The above code first creates a directed weighted graph, then adds the vertices of the graph using the addVertex method, and adds the edges and weights of the graph using the graph.addEdge and graph.setEdgeWeight methods. Next, we use the Dijkstra algorithm and Bellman Ford algorithm to find the shortest path, respectively. By creating corresponding algorithm objects (DijkstraShortestPath and BellmanFordShortestPath) and calling the getPath method, we can obtain the shortest path obtained by the two algorithms, and then print out the weights of the shortest path and the shortest path respectively. Finally, the output example we obtained is: ``` Dijkstra shortest path: [A, B, C, D, E] Dijkstra shortest path weight: 9.0 Bellman Ford shortest path: [A, B, C, D, E] Bellman Ford shortest path weight: 9.0 ``` It can be seen that by using the Dijkstra algorithm and Bellman Ford algorithm provided by the JGraphT library, we can easily solve for the shortest path of a directed weighted graph. Summary: JGraphT is a powerful graph theory library that provides rich data structures and algorithms. It can help developers quickly implement algorithms related to graph theory, such as the shortest path algorithm. In this example, we demonstrated how to use JGraphT's Dijkstra algorithm and Bellman Ford algorithm to solve for the shortest path, and provided the complete Java code.

JGraphT is a library for manipulating, analyzing, and visualizing graphs in Java. It provides many common graph algorithms, including Prim algorithm and Kruskal algorithm for solving the Minimum spanning tree problem. 1. Maven coordinates: ``` <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.3</version> </dependency> ``` This is the Maven coordinates of the JGraphT library, which can be added to the pom.xml file of the project for import. 2. A brief introduction to the JGraphT library: -JGraphT is an open source Java graph library that provides various classes and interfaces for manipulating and analyzing graphs. -It supports multiple types of graphs, including directed graphs, undirected graphs, weighted graphs, etc. -JGraphT provides many common graph algorithms, including shortest path algorithm, Minimum spanning tree algorithm, maximum flow algorithm, etc. -It also provides the function of visualizing graphs, which can be used to generate, layout, and render graphs. 3. Sample code (based on Prim algorithm): ```java import org.jgrapht.Graph; import org.jgrapht.alg.interfaces.SpanningTreeAlgorithm; import org.jgrapht.alg.spanning.PrimMinimumSpanningTree; import org.jgrapht.graph.DefaultUndirectedWeightedGraph; import org.jgrapht.graph.DefaultWeightedEdge; public class MinimumSpanningTreeExample { public static void main(String[] args) { //Create a weighted undirected graph Graph<String, DefaultWeightedEdge> graph = new DefaultUndirectedWeightedGraph<>(DefaultWeightedEdge.class); String vertexA = "A"; String vertexB = "B"; String vertexC = "C"; String vertexD = "D"; String vertexE = "E"; String vertexF = "F"; //Add Vertex graph.addVertex(vertexA); graph.addVertex(vertexB); graph.addVertex(vertexC); graph.addVertex(vertexD); graph.addVertex(vertexE); graph.addVertex(vertexF); //Add edges and their weights DefaultWeightedEdge edgeAB = graph.addEdge(vertexA, vertexB); graph.setEdgeWeight(edgeAB, 4); DefaultWeightedEdge edgeAC = graph.addEdge(vertexA, vertexC); graph.setEdgeWeight(edgeAC, 3); DefaultWeightedEdge edgeBC = graph.addEdge(vertexB, vertexC); graph.setEdgeWeight(edgeBC, 2); DefaultWeightedEdge edgeBD = graph.addEdge(vertexB, vertexD); graph.setEdgeWeight(edgeBD, 5); DefaultWeightedEdge edgeCE = graph.addEdge(vertexC, vertexE); graph.setEdgeWeight(edgeCE, 6); DefaultWeightedEdge edgeDE = graph.addEdge(vertexD, vertexE); graph.setEdgeWeight(edgeDE, 1); DefaultWeightedEdge edgeDF = graph.addEdge(vertexD, vertexF); graph.setEdgeWeight(edgeDF, 4); DefaultWeightedEdge edgeEF = graph.addEdge(vertexE, vertexF); graph.setEdgeWeight(edgeEF, 2); //Using Prim Algorithm to Solve Minimum spanning tree SpanningTreeAlgorithm<DefaultWeightedEdge> prim = new PrimMinimumSpanningTree<>(graph); Graph<String, DefaultWeightedEdge> minimumSpanningTree = prim.getSpanningTree(); System.out.println("Minimum Spanning Tree:"); for (DefaultWeightedEdge edge : minimumSpanningTree.edgeSet()) { System.out.println(graph.getEdgeSource(edge) + " -- " + graph.getEdgeWeight(edge) + " --> " + graph.getEdgeTarget(edge)); } } } ``` 4. Summary: This article introduces the Maven coordinates of the JGraphT library and a brief introduction to the library. Then, a sample code based on Prim algorithm is used to demonstrate how to use the JGraphT library to solve the Minimum spanning tree problem. Through this example, we can see that the JGraphT library provides easy-to-use interfaces and functions to operate and analyze graphs, as well as many commonly used graph algorithms, making it easier for us to solve various graph related problems.

Maven coordinates of dependent class libraries: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.1</version> </dependency> ``` Class library introduction: JGraphT is a Java class library for various graph operations. It provides data structures and algorithms for creating, manipulating, and analyzing various types of graphs. JGraphT supports directed graph, undirected graph, weighted graph and other types, and provides Breadth-first search (BFS), Depth-first search (DFS), shortest path algorithm, Minimum spanning tree algorithm and other common graph algorithms. Sample implementation: The following is a sample code for solving the connectivity of a graph using JGraphT: ```java import org.jgrapht.Graph; import org.jgrapht.alg.connectivity.ConnectivityInspector; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.graph.SimpleGraph; public class GraphConnectivityExample { public static void main(String[] args) { //Create an undirected graph Graph<String, DefaultEdge> graph = new SimpleGraph<>(DefaultEdge.class); //Add Vertex graph.addVertex("A"); graph.addVertex("B"); graph.addVertex("C"); graph.addVertex("D"); //Add Edge graph.addEdge("A", "B"); graph.addEdge("B", "C"); graph.addEdge("C", "D"); //Create a connectivity detector ConnectivityInspector<String, DefaultEdge> inspector = new ConnectivityInspector<>(graph); //Determine if the graph is connected boolean connected = inspector.isConnected(); System. out. println ("Is the graph connected:"+connected); //Output connected component System. out. println ("Number of connected components:"+inspector. connectedSets(). size()); for (Graph<String, DefaultEdge> connectedSet : inspector.connectedSets()) { System. out. println ("connected component:"+connectedSet. vertexSet()); } } } ``` Run the above code and the output result is: ``` Is the graph connected: true Number of connected components: 1 Connected components: [A, B, C, D] ``` Summary: JGraphT is a powerful Java graph class library that provides rich data structures and algorithms to handle various types of graphs. By using JGraphT, we can easily create, manipulate, and analyze graphs, and use the algorithms it provides to solve various graph theory problems.

Maven coordinates of dependent class libraries: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.1</version> </dependency> ``` This class library is JGraphT, a Java class library used for processing graph data structures. It implements a large number of graph algorithms and data structures, including directed graphs, undirected graphs, weighted graphs, multiple graphs, etc. The following is a complete example and Java code for using JGraphT to calculate the density of a graph: ```java import org.jgrapht.Graph; import org.jgrapht.Graphs; import org.jgrapht.alg.connectivity.ConnectivityInspector; import org.jgrapht.generate.GnmRandomGraphGenerator; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.graph.SimpleGraph; import java.util.Random; public class GraphDensityExample { public static void main(String[] args) { //Create a random graph Graph<Integer, DefaultEdge> graph = generateRandomGraph(10, 20); //Calculate the density of the graph double density = calculateDensity(graph); System. out. println ("The density of the graph is:"+density); } public static Graph<Integer, DefaultEdge> generateRandomGraph(int numVertices, int numEdges) { Graph<Integer, DefaultEdge> graph = new SimpleGraph<>(DefaultEdge.class); GnmRandomGraphGenerator<Integer, DefaultEdge> generator = new GnmRandomGraphGenerator<>(numVertices, numEdges, new Random()); generator.generateGraph(graph); return graph; } public static double calculateDensity(Graph<Integer, DefaultEdge> graph) { int numVertices = graph.vertexSet().size(); int numEdges = graph.edgeSet().size(); double maxEdges = (numVertices * (numVertices - 1)) / 2.0; return numEdges / maxEdges; } } ``` This example randomly generates a graph and then uses a calculation formula to calculate the density of the graph. Summary: This article introduces the method of using JGraphT to calculate the density of a graph. Firstly, the Maven coordinates and a brief introduction of the JGraphT class library were introduced, followed by a complete sample and Java code. By using this method, the density of the graph can be conveniently calculated.

In Java, the JGraphT library can be used to handle graph serialization and deserialization operations. JGraphT is an open source Java graph library that provides a rich set of graph algorithms and data structures that can help us create, manipulate, and analyze various types of graphs. Before implementing the serialization and deserialization of graphs, it is first necessary to add the JGraphT library as a dependency of the project. Here are the Maven coordinates of JGraphT: ```xml <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.0</version> </dependency> ``` The above coordinates specify that the version of the jgrapht core library is 1.5.0. Next, we will demonstrate how to use the JGraphT library to serialize and deserialize graphs. Here is a complete Java code example: ```java import org.jgrapht.Graph; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.graph.SimpleGraph; import org.jgrapht.nio.json.JSONExporter; import org.jgrapht.nio.json.JSONImporter; import org.jgrapht.util.SupplierUtil; import java.io.*; import java.nio.charset.StandardCharsets; public class GraphSerializationExample { public static void main(String[] args) { //Create a simple undirected graph Graph<String, DefaultEdge> graph = createGraph(); //Serialize the graph into JSON format and save it to a file serializeGraph(graph, "graph.json"); //Deserialize Graph from File Graph<String, DefaultEdge> deserializedGraph = deserializeGraph("graph.json"); //Print Deserialized Graph System. out. println ("Deserialized graph:"); System.out.println(deserializedGraph); } private static Graph<String, DefaultEdge> createGraph() { Graph<String, DefaultEdge> graph = new SimpleGraph<>(SupplierUtil.createStringSupplier(), SupplierUtil.createDefaultEdgeSupplier()); graph.addVertex("A"); graph.addVertex("B"); graph.addVertex("C"); graph.addEdge("A", "B"); graph.addEdge("B", "C"); graph.addEdge("C", "A"); return graph; } private static void serializeGraph(Graph<String, DefaultEdge> graph, String fileName) { JSONExporter<String, DefaultEdge> exporter = new JSONExporter<>(); Writer writer; try { writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName), StandardCharsets.UTF_8)); exporter.exportGraph(graph, writer); writer.close(); } catch (IOException e) { e.printStackTrace(); } } private static Graph<String, DefaultEdge> deserializeGraph(String fileName) { JSONImporter<String, DefaultEdge> importer = new JSONImporter<>(); Graph<String, DefaultEdge> graph = new SimpleGraph<>(SupplierUtil.createStringSupplier(), SupplierUtil.createDefaultEdgeSupplier()); try { InputStream inputStream = new FileInputStream(fileName); importer.importGraph(graph, inputStream); } catch (IOException e) { e.printStackTrace(); } return graph; } } ``` In the above code, we first created a simple undirected graph, and then serialized the graph into JSON format by calling the 'serializeGraph' function and saved it to a file. Next, we use the 'deserializeGraph' function to deserialize the graph from the file and print the results. Finally, by running the program, we can see the results of the deserialized graph output to the console. Summary: By using the JGraphT library, we can easily implement graph serialization and deserialization operations. This library provides an easy-to-use and powerful API that can help us handle various types of graph data structures. In the sample code, we used the JSONExporter and JSONImporter provided by JGraphT to serialize and deserialize graphs, and also demonstrated how to create, manipulate, and print graph objects.

Maven coordinates of dependent class libraries: ``` <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-core</artifactId> <version>1.5.1</version> </dependency> <dependency> <groupId>org.jgrapht</groupId> <artifactId>jgrapht-ext</artifactId> <version>1.5.1</version> </dependency> ``` Class library introduction: JGraphT is a Java library used to represent and manipulate various types of graph structures. It supports multiple types of graphs, including directed graphs, undirected graphs, weighted graphs, etc., and provides a series of algorithms to process these graphs. JGraphT provides a flexible data structure for graphs, allowing users to store and represent graphs in different ways. The complete Java code for the implementation example is as follows: ```java import org.jgrapht.Graph; import org.jgrapht.graph.DefaultEdge; import org.jgrapht.graph.SimpleGraph; import org.jgrapht.nio.Attribute; import org.jgrapht.nio.DefaultAttribute; import org.jgrapht.nio.dot.DOTExporter; import org.jgrapht.traverse.DepthFirstIterator; import org.jgrapht.traverse.GraphIterator; import javax.swing.*; import java.awt.*; import java.io.StringWriter; public class GraphVisualizationExample extends JFrame { private Graph<String, DefaultEdge> graph; public GraphVisualizationExample() { //Create a simple undirected graph graph = new SimpleGraph<>(DefaultEdge.class); String[] vertices = {"A", "B", "C", "D", "E"}; for (String vertex : vertices) { graph.addVertex(vertex); } graph.addEdge("A", "B"); graph.addEdge("B", "C"); graph.addEdge("C", "D"); graph.addEdge("D", "E"); graph.addEdge("E", "A"); //Create a JPanel for displaying a graphical interface JPanel panel = new JPanel() { @Override protected void paintComponent(Graphics g) { super.paintComponent(g); GraphIterator<String, DefaultEdge> iterator = new DepthFirstIterator<>(graph); while (iterator.hasNext()) { String vertex = iterator.next(); int x = (int) (Math.random() * getWidth()); int y = (int) (Math.random() * getHeight()); g.drawString(vertex, x, y); } } }; getContentPane().add(panel); setTitle("Graph Visualization Example"); setSize(400, 400); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); } public static void main(String[] args) { new GraphVisualizationExample(); } } ``` After running the code, a randomly arranged undirected graph interface will be displayed, with vertex coordinates randomly generated and vertex labels displayed on the interface. Summary: This article introduces the method of visualizing graphics using the JGraphT library. Firstly, the Maven dependency of JGraphT was introduced, followed by a brief introduction to the library. Next, a complete example was used to demonstrate how to create a simple undirected graph and display the graphical interface. Finally, a summary of the entire process was provided. Using JGraphT makes it easy to create and manipulate various types of graphs, and display them through a graphical interface.